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Showing papers on "Antimicrobial peptides published in 1996"


Journal ArticleDOI
TL;DR: The antimicrobial proteins, CAP37/azurocidin and defensins H NP-1 and HNP-2, are identified as potent neutrophil-derived chemoattractants for T-cells, which represent primordial antimicrobial peptides which may have evolved into acute inflammatory cell-derived signals that mobilize immunocompetent T- cells and other inflammatory cells.

574 citations


Journal ArticleDOI
TL;DR: Peptide antibacterial activity was tested against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus and the peptides were much less lytic toward human erythrocytes than 3T3 cells.
Abstract: De novo antimicrobial peptides with the sequences: (KLAKKLA)n, (KLAKLAK)n (where n = 1, 2, 3), (KALKALK)3, (KLGKKLG)n, and (KAAKKAA)n (where n = 2, 3), were prepared as the C-terminus amides. These peptides were designed to be perfectly amphipathic in helical conformations. Peptide antibacterial activity was tested against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Peptide cytotoxicity was tested against human erythrocytes and 3T3 mouse fibroblasts. The 3T3 cell testing was a much more sensitive test of cytotoxicity. The peptides were much less lytic toward human erythrocytes than 3T3 cells. Peptide secondary structure in aqueous solution, sodium dodecylsulfate micelles, and phospholipid vesicles was estimated using circular dichroism spectroscopy. The leucine/alanine-containing 21-mers were bacteriostatic at 3−8 μM and cytotoxic to 3T3 cells at about 10 μM concentrations. The leucine/alanine- or leucine/glycine-containing 14-mers and the leucine/glycine 21-mer were bacteriostat...

499 citations


Journal ArticleDOI
TL;DR: Data suggest that resistance to the polymyxin-CAP family is controlled by a cascade of regulatory protein expression that activates transcription upon environmental sensing.
Abstract: Antimicrobial cationic peptides are a host defense mechanism of many animal species including mammals, insects, and amphibians. Salmonella typhimurium is an enteric and intracellular pathogen that interacts with antimicrobial peptides within neutrophil and macrophage phagosomes and at intestinal mucosal surfaces. The Salmonella spp. virulence regulators, PhoP and PhoQ, activate the transcription of genes (pag) within macrophage phagosomes necessary for resistance to cationic antimicrobial peptides. One PhoP-activated gene, pagB, forms an operon with pmrAB (5' pagB-pmrA-pmrB 3'), a two-component regulatory system involved in resistance to the antimicrobial peptides polymyxin, azurocidin (CAP37), bactericidal/permeability-increasing protein (BPI or CAP57), protamine, and polylysine. Expression of pmrAB increased transcription of pagB-pmrAB by activation of a promoter 5' to pagB. pmrAB is also expressed from a second promoter, not regulated by PhoP-PhoQ or PmrA-PmrB, located within the pagB coding sequence. S. typhimurium strains with increased pag locus expression were demonstrated to be polymyxin resistant because of induction of pagB-pmrAB; however, PmrA-PmrB was not responsible for the increased sensitivity of PhoP-null mutants to NP-1 defensin. Therefore, PhoP regulates at least two separate networks of genes responsible for cationic antimicrobial peptide resistance. These data suggest that resistance to the polymyxin-CAP family is controlled by a cascade of regulatory protein expression that activates transcription upon environmental sensing.

412 citations


Journal ArticleDOI
TL;DR: It is argued that circulating antimicrobial peptides represent an ancient host defense mechanism that predated the separation between molluscs and arthropods at the root of the Cambrian, about 545 million years ago.

359 citations


Journal ArticleDOI
TL;DR: Study of immune-deficient mutants of Drosophila has indicated that distinct pathways control the antibacterial and antifungal responses in this species.

353 citations


Journal ArticleDOI
TL;DR: In this article, the cDNAs encoding the seed antimicrobial peptides (AMPs) from Mirabilis jalapa (Mj-AMP2) and Amaranthus caudatus (Ac-AMP 2) have been characterized and it was found that AMPs are processed from a precursor preprotein and preproprotein, respectively.
Abstract: The cDNAs encoding the seed antimicrobial peptides (AMPs) from Mirabilis jalapa (Mj-AMP2) and Amaranthus caudatus (Ac-AMP2) have previously been characterized and it was found that Mj-AMP2 and Ac-AMP2 are processed from a precursor preprotein and preproprotein, respectively [De Bolle et al., Plant Mol Biol 28:713-721 (1995) and 22:1187-1190 (1993), respectively]. In order to study the processing, sorting and biological activity of these antimicrobial peptides in transgenic tobacco, four different gene constructs were made: a Mj-AMP2 wild-type gene construct, a Mj-AMP2 mutant gene construct which was extended by a sequence encoding the barley lectin carboxyl-terminal propeptide, a known vacuolar targeting signal [Bednarek and Raikhel, Plant Cell 3: 1195-1206 (1991)]; an Ac-AMP2 wild-type gene construct; and finally, an Ac-AMP2 mutant gene construct which was truncated in order to delete the sequence encoding the genuine carboxyl-terminal propeptide. Processing and localization analysis indicated that an isoform of Ac-AMP2 with a cleaved-off carboxyl-terminal arginine was localized in the intercellular fluid fraction of plants expressing either wild-type or mutant gene constructs. Mj-AMP2 was recovered extracellularly in plants transformed with Mj-AMP2 wild-type gene construct, whereas an Mj-AMP2 isoform with a cleaved-off carboxyl-terminal arginine accumulated intracellularly in plants expressing the mutant precursor protein with the barley lectin propeptide. The in vitro antifungal activity of the AMPs purified from transgenic tobacco expressing any of the four different precursor proteins was similar to that of the authentic proteins. However, none of the transgenic plants showed enhanced resistance against infection with either Botrytis cinerea or Alternaria longipes.

330 citations


Journal ArticleDOI
TL;DR: The peptides predicted from the sequence of the cloned cDNAs as well as several structurally related peptides could be isolated from the skin secretion of R. temporaria, which are the smallest antibacterial peptides hitherto found in nature.
Abstract: A cDNA library from the skin of Rana temporaria has been screened using a cDNA fragment probe that encodes the signal peptide of the precursor of esculentin from the skin secretion of Rana esculenta. With this approach, the cDNAs encoding the precursors of three peptides were isolated. Subsequently, the peptides predicted from the sequence of the cloned cDNAs as well as several structurally related peptides could be isolated from the skin secretion of R. temporaria. These peptides, which were named temporins, have a length of 10-13 residues and show some sequence similarity to hemolytic peptides isolated from Vespa venom [Argiolas, A. & Pisano, J. J. (1984) J. Biol. Chem. 259, 10106-10111]. Natural and synthetic temporins have antibacterial activity against gram-positive bacteria, but they are not hemolytic. Temporins are the smallest antibacterial peptides hitherto found in nature.

329 citations


Journal ArticleDOI
TL;DR: The peptide is bactericidal and fungicidal, exhibiting the largest antimicrobial spectrum observed so far for an insect defense peptide, and is proposed for the name thanatin.
Abstract: Immune challenge to the insect Podisus maculiventris induces synthesis of a 21-residue peptide with sequence homology to frog skin antimicrobial peptides of the brevinin family. The insect and frog peptides have in common a C-terminally located disulfide bridge delineating a cationic loop. The peptide is bactericidal and fungicidal, exhibiting the largest antimicrobial spectrum observed so far for an insect defense peptide. An all-D-enantiomer is nearly inactive against Gram-negative bacteria and some Gram-positive strains but is fully active against fungi and other Gram-positive bacteria, suggesting that more than one mechanism accounts for the antimicrobial activity of this peptide. Studies with truncated synthetic isoforms underline the role of the C-terminal loop and flanking residues for the activity of this molecule for which we propose the name thanatin.

303 citations


Journal ArticleDOI
TL;DR: Paneth cell defensins are early markers of crypt ontogeny and are therefore useful in studies of lineage determination in the intestinal epithelium and should be of interest to define biochemical and biophysical attributes that adapt these peptides to barrier function of mucosal surfaces.
Abstract: Paneth cells are epithelial granulocytes at the base of the crypts of Lieberkuhn in the small intestine of many mammalian species. These secretory cells contribute to mucosal barrier function by the apical release of granules containing a variety of antimicrobial products, including peptides termed cryptdins, for crypt defensins. In mice, six Paneth cell defensins have been characterized at the peptide level that have potent antimicrobial activities equivalent to or greater than that of rabbit neutrophil defensin NP-1. Cryptdin peptides that differ only by single amino acid substitutions have been shown to exhibit a high degree of specificity against certain target microorganisms. Cryptdins are coded by separate, two-exon genes that are located on chromosome 8 in both mice and humans. Human Paneth cells contain high levels of two different defensin mRNAs, but in mice at least 19 cryptdin isoforms are predicted from cDNA sequencing data. The mouse cryptdin-4 gene is expressed with positional specificity along the longitudinal intestinal axis, and cryptdin genes are active in the intestinal epithelium prior to Paneth cell differentiation. Accordingly, Paneth cell defensins are early markers of crypt ontogeny and are therefore useful in studies of lineage determination in the intestinal epithelium. Because cryptdins mediate innate immunity in the hostile environment of the intestinal lumen, it should be of interest to define biochemical and biophysical attributes that adapt these peptides to barrier function of mucosal surfaces.

291 citations


Journal ArticleDOI
TL;DR: Peptides corresponding to these sequences have been chemically synthesized and shown to exert a potent antimicrobial activity against Gram-negative and Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus, and fungi and fungi.

245 citations


Journal ArticleDOI
TL;DR: Three distinct antimicrobial peptides are isolated from the hemolymph of unchallenged scorpions of the species Androctonus australis, which are fully characterized by Edman degradation, electrospray ionization mass spectrometry, and matrix-assisted laser desorption/ionization mass Spectrometry.

Journal ArticleDOI
TL;DR: It is demonstrated that the intramolecular disulfide bonds of protegrins are required for their antiparallel beta-sheet conformation in membrane-mimetic environments and for their potent antimicrobial activity in media containing NaCl concentrations comparable to those found in serum and extracellular fluids.
Abstract: Protegrins are 2-kDa antimicrobial peptides that contain 16–18 amino acid residues and two intramolecular disulfide bonds. We studied the contribution of these disulfide bonds to the bactericidal activity of protegrins in physiological concentrations of NaCl by comparing protegrin PG-1 with variants that lacked one or both cysteine disulfides. Whereas the bactericidal and liposome-lytic properties of protegrin PG-1 were enhanced by adding 100 mM NaCl to the phosphate-buffered medium, NaCl addition strongly inhibited the effects of its linearized, disulfide-free variant, [A6, A8, A13, A15]protegrin-1. Whereas protegrin PG-1 manifested β-sheet structure by CD (circular dichroism) and ATR-FTIR (attenuated-total-reflectance-Fourier-transform-infrared) spectroscopy in buffer or membrane-mimetic environments, [A6, A8, A13, A15]protegrin-1 manifested disordered structure in phosphate buffer and α-helical characteristics in membrane-mimetic environments. Both single-disulfide protegrin variants, [A8, A13]protegrin-1 and [A6, A15]protegrin-1, assumed β-sheet conformations with liposomes that simulated bacterial membranes, and both retained substantial bactericidal activity when 100 mM NaCl was present. These findings demonstrate that the intramolecular disulfide bonds of protegrins are required for their antiparallel β-sheet conformation in membrane-mimetic environments and for their potent antimicrobial activity in media containing NaCl concentrations comparable to those found in serum and extracellular fluids.

Journal ArticleDOI
TL;DR: A 37-residue cationic antimicrobial peptide named mesentericin Y 10537 was purified to homogeneity from cell-free culture supernatant of the Gram-positive bacterium Leuconostoc mesenteroides as discussed by the authors.

Journal ArticleDOI
TL;DR: It is suggested that antimicrobial peptides such as defensins and protegrin from porcine leukocytes may represent an important component of the host defense mechanism against M. tuberculosis and offer a potential new approach to therapy.
Abstract: Three independent assay methods were used to investigate the activities of antimicrobial peptides (human and rabbit defensins and protegrin from porcine leukocytes) against Mycobacterium tuberculosis in vitro. M. tuberculosis H37Ra was cultured in the presence of human neutrophil peptide 1, synthetic rabbit neutrophil peptide 1, or porcine protegrin 1 at 37 degrees C for 6 to 48 h, and antimycobacterial activity was measured by CFU assay. These peptides at a concentration of 50 microg/ml showed significant antibacterial effects on M. tuberculosis after 24 and 48 h of incubation (85.9 to 97.5% at 24 h and 91.6 to 99.4% at 48 h). A radiometric method and a radial diffusion assay confirmed these observations. Antibacterial activity against M. tuberculosis was independent of calcium (1.0 mM) or magnesium (1.0 mM) and not inhibited by sodium chloride (100 mM). The optimal pH for antibacterial activity against M. tuberculosis was greater than 4.0. Three clinical isolates of M. tuberculosis were also studied, and these peptides showed 86.3 to 99.0% reduction in CFU of these organisms. Morphological studies using scanning electron microscopy showed that defensins caused lesions on the surface of H37Ra. These observations suggest that antimicrobial peptides such as defensins and protegrins may represent an important component of the host defense mechanism against M. tuberculosis and offer a potential new approach to therapy.

Journal ArticleDOI
TL;DR: Defensins and protegrin-like peptides are likely to play a considerable role in innate immunity and may provide molecular templates that can be used to generate novel antibiotics for topical and systemic use.
Abstract: Although newly recognized, endogenous cystine-stabilized beta-sheet antimicrobial peptides have ancient origins. These peptides can arm circulating phagocytes and cells of the gastrointestinal, respiratory, and genitourinary tracts to resist invasion by bacteria, mycobacteria, fungi, and enveloped viruses. Defensins and protegrin-like peptides are likely to play a considerable role in innate immunity and may provide molecular templates that can be used to generate novel antibiotics for topical and systemic use.

Journal ArticleDOI
TL;DR: It is demonstrated that small intestinal Paneth cells secrete antimicrobial peptides in vivo, that this secretion is regulated by the autonomic (parasympathetic) cholinergic nervous system, and that the release of antimicrobial molecules can be triggered by the presence of bacterial LPS in the intestinal lumen.
Abstract: We examined the secretion of antimicrobial proteins and peptides into surgically isolated and continuously perfused segments of rat small intestine. Up to nine discrete antimicrobial molecules appeared in the intestinal perfusates following intravenous administration of bethanechol, a cholinergic agonist, or intralumenal instillation of lipopolysaccharide (LPS). Among them were three markers of Paneth cell secretion: lysozyme; type II (secretory) phospholipase A2; and at least one intestinal defensin, RIP-3, that appeared to be an alternatively processed variant of the rat neutrophil defensin RatNP-3. Both bethanechol- and LPS-stimulated intestinal lumenal perfusates (washings) contained molecules that killed Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes in vitro. These molecules were more active against the avirulent S. typhimurium strain 7953S (phoP) than against its virulent parent, S. typhimurium 14028S. These data demonstrate that small intestinal Paneth cells secrete antimicrobial peptides in vivo, that this secretion is regulated by the autonomic (parasympathetic) cholinergic nervous system, and that the release of antimicrobial molecules can be triggered by the presence of bacterial LPS in the intestinal lumen.

Journal ArticleDOI
TL;DR: Protegrin-mediated inactivation of chlamydiae occurred rapidly, was relatively independent of the presence of serum, and was effective against serovars L2, D, and H, suggesting that protegrins and related molecules could serve as prototypes for topical agents to prevent sexually transmitted chlamydial infection.
Abstract: We compared the susceptibilities of Chlamydia trachomatis elementary bodies (EBs) to human defensin HNP-2 and porcine protegrin PG-1, cysteine-rich beta-sheet antimicrobial peptides produced by mammalian leukocytes. Although both peptides protected McCoy cell monolayers from infection by chlamydial EBs, protegrins were especially potent. Protegrin-mediated inactivation of chlamydiae occurred rapidly, was relatively independent of the presence of serum, and was effective against serovars L2, D, and H. Protegrin-treated EBs showed striking morphological changes, with obvious damage to their limiting membranes and loss of their cytoplasmic contents and nucleoid. Their effectiveness against chlamydial EBs and other sexually transmitted pathogens combined with their relative lack of cytotoxicity suggests that protegrins and related molecules could serve as prototypes for topical agents to prevent sexually transmitted chlamydial infection.

Journal ArticleDOI
TL;DR: In this paper, a 46 residue sequence named lactoferricin H was found to be responsible for the antimicrobial properties of human lactoferrin and derived from dermaseptin and magainins.

Journal ArticleDOI
TL;DR: Although each N. gonorrhoeae strain was resistant to human neutrophil defensins, all six were exquisitely sensitive to protegrins, a family of small beta-sheet antimicrobial peptides recently identified in porcine leukocytes, which show promise for development as topical agents to avert sexually transmitted diseases.
Abstract: We developed a sensitive and quantitative radial diffusion method to ascertain the susceptibility of six strains of Neisseria gonorrhoeae to antimicrobial peptides derived from mammalian leukocytes. The test organisms included the well-characterized serum-resistant FA19 and serum-sensitive F62 strains plus four antibiotic-resistant clinical isolates. Although each N. gonorrhoeae strain was resistant to human neutrophil defensins, all six were exquisitely sensitive to protegrins, a family of small beta-sheet antimicrobial peptides recently identified in porcine leukocytes. Protegrin-treated N. gonorrhoeae became vacuolated and had striking membrane changes when viewed by transmission and scanning electron microscopy. Because low concentrations of protegrins can also inactivate Chlamydia trachomatis and human immunodeficiency virus, they show promise for development as topical agents to avert sexually transmitted diseases.

Patent
31 May 1996
TL;DR: In this paper, a novel class of cationic peptides having antimicrobial activity is provided, which are particularly useful for inhibiting endotoxaemia in a subject, and methods for inhibited the growth of bacteria utilizing the peptides of the invention.
Abstract: A novel class of cationic peptides having antimicrobial activity is provided. Examples of such peptides include NH2-KWKSFIKKLTTAVKKVLTTGLPALIS-COOH (SEQ ID NO:1) and NH2-KWKSFIKKLTSAAKKVVTTAKPLISS-COOH (SEQ ID NO:2). Also provided are methods for inhibiting the growth of bacteria utilizing the peptides of the invention. The peptides are particularly useful for inhibiting endotoxaemia in a subject.

Journal ArticleDOI
TL;DR: Four of the induced peptides isolated from Palomena are closely related small, strongly cationic, proline-rich peptides, and the fifth is a 43-residue novel isoform of insect defensins.

Journal ArticleDOI
TL;DR: The isolation of a truncated, monomeric form of this protein, lacking the cysteine-containing antimicrobial dodecapeptide, indicates that dimerization occurs via disulfide bridge formation at the level of the C-terminal domain and that the dodecAPEptide is likely released as a dimer from its precursor.
Abstract: Cathelicidins are a novel family of antimicrobial peptide precursors from mammalian myeloid cells. They are characterized by a conserved N-terminal region while the C-terminal antimicrobial domain can vary considerably in both primary sequence and length. Four cathelicidins, proBac5, proBac7, prododecapeptide and proBMAP-28, have been concurrently purified from bovine neutrophils, using simple and rapid methodologies. The correlation of ES-MS data from the purified proteins with their cDNA-deduced sequences has revealed several common features of their primary sequence, such as the presence of N-terminal 5-oxoproline (pyroglutamate) residues and two disulfide bridges in a 1–2, 3–4 arrangement. The N-terminal domains of the cathelicidins present one or two Asp-Pro bonds, which are particularly acid-labile in proBac5 and proBac7, but stable in prododecapeptide. This suggests that the spatial organization around these bonds may vary in different cathelicidins, and favour hydrolysis in some cases. An unexpected feature of the prododecapeptide is that it exists as dimers formed by three possible combinations of its two isoforms. The isolation of a truncated, monomeric form of this protein, lacking the cysteine-containing antimicrobial dodecapeptide, indicates that dimerization occurs via disulfide bridge formation at the level of the C-terminal domain and that the dodecapeptide is likely released as a dimer from its precursor. Sequence-based secondary structure predictions and CD results indicate for cathelicidins a 30–50% content of extended conformation and <20% content of α-helical conformation, with the α-helical segment placed near the N-terminus. Finally, similarity searching and topology-based structure prediction underline a significant sequential and structural similarity between the conserved N-terminal domain of cathelicidins and cystatin-like domains, placing this family within the cystatin superfamily. When assayed against cathepsin L, unlike the potent cystatin inhibitors, three of the four cathelicidins show only a poor inhibitory activity (Ki= 0.6–3 μM).

Journal ArticleDOI
TL;DR: Sequencing of the 16S RNA of the small ribosomal subunit indicate that the microbial world is much larger than generally appreciated.
Abstract: In the last 2 years (1994-95), two symposium volumes and three reviews have been published that were fully devoted to peptide antibiotics (antibacterial peptides or antimicrobial peptides). Since the field has been growing rapidly, this review is largely a follow-up of new results published in the last 2 years. Sequencing of the 16S RNA of the small ribosomal subunit indicate that the microbial world is much larger than generally appreciated. The importance of the natural flora is stressed and its effect on the evolution of peptide antibiotics and immunity in general is discussed.

Journal ArticleDOI
TL;DR: The results indicate the presence of an rpoS- and phoP-independent pathway important to starvation- and stationary-phase-induced resistance to membrane-permeabilizing antimicrobial agents.
Abstract: A common stress encountered by Salmonella serovars involves exposure to membrane-permeabilizing antimicrobial peptides and proteins such as defensins, cationic antibacterial proteins, and polymyxins. We wanted to determine if starvation induces cross-resistance to the membrane-permeabilizing antimicrobial peptide polymyxin B (PmB). We report here that starved and stationary-phase (Luria-Bertani [LB] medium) cells exhibited ca. 200- to 1,500-fold-higher (cross-)resistance to a 60-min PmB challenge than log-phase cells. Genetic analysis indicates that this PmB resistance involves both phoP-dependent and -independent pathways. Furthermore, both pathways were sigma(S) independent, indicating that they are different from other known sigma(S) -dependent cross-resistance mechanisms. Additionally, both pathways were important for PmB resistance early during C starvation and for cells in stationary phase in LB medium. However, only the phoP-independent pathway was important for P-starvation-induced PmB resistance and the sustained PmB resistance seen in 24-h-C-starved (and N-starved) or stationary-phase cells in LB medium. The results indicate the presence of an rpoS- and phoP-independent pathway important to starvation- and stationary-phase-induced resistance to membrane-permeabilizing antimicrobial agents.

Journal ArticleDOI
TL;DR: The presence of hydrophobic residues appears to have a significant effect on the process of antibacterial activity of the 15‐residue hybrid peptide analogues, which showed voltage‐dependent conductance changes and are capable of forming ion‐pores in planar lipid bilayers.
Abstract: The design of cecropin-melittin hybrid analogues is of interest due to the similarities in the structure of the antimicrobial peptides cecropin and melittin but differences in their lytic properties. We suspected that a hydrophobic residue in position 2 of milittin (Ile8 in the hybrid) plays an important role in the activity of the 15-residue hybrid, KWKLFKKIGAVLKVL-NH2, [CA(1-7)M(2-9)NH2] and have now examined its role in the analogue toward five test bacteria. Deletion of Ile8 reduced activity, and it was not restored by lengthening to 15 residues by addition of another threonine at the C-terminus. Replacement of Ile8 by a hydrophobic leucine maintained good activity and Ala8 was equally active for four organisms, although less active against Staphylococcus aureus. Replacement by the hydrophilic Ser8 strongly reduced potency against all five organisms. Deletion of Leu15 decreased activity, but addition of Thr16 maintained good activity. The presence of hydrophobic residues appears to have a significant effect on the process of antibacterial activity. These peptide analogues showed voltage-dependent conductance changes and are capable of forming ion-pores in planar lipid bilayers. The antibacterial action of the peptides is thought to be first an ionic interaction with the anionic phosphate groups of the membrane followed by interaction with the hydrocarbon core of the membrane and subsequent reorientation into amphipathic alpha-helical peptides that form pores (ion-channels), which span the membrane. The analogue also showed an increase in alpha-helicity with an increase in hexafluoro 2-propanol concentration.

Patent
21 Mar 1996
TL;DR: In this paper, an anti-fungal peptides derived from or based on Domain III (amino acids 142-169) of bactericidal/permeability-increasing protein (BPI) and in vivo or in vitro uses of such peptides were described.
Abstract: The present invention relates generally to anti-fungal peptides derived from or based on Domain III (amino acids 142-169) of bactericidal/permeability-increasing protein (BPI) and in vivo or in vitro uses of such peptides.


Journal ArticleDOI
15 Jun 1996-Virology
TL;DR: The data suggest that the inhibitory peptides may act by interacting with cell-surface molecules involved in viral infection.

Journal ArticleDOI
TL;DR: The results suggest that in the intestine the enterocytes could develop antimicrobial defenses participating in the protection of the gut epithelium against enterovirulent microorganisms.

Journal ArticleDOI
TL;DR: According to preliminary results, fusion to the large (±78 kDa) amine oxidase carrier particularly stabilizes the peptides and prevents them from proteolysis and after partial purification, the fusion partners were readily separated by factor Xa treatment.
Abstract: We describe the synthesis and purification of two functional peptides, namely human insulin-like growth factor II (IGF-II) and Xenopus laevis magainin II in Hansenula polymorpha after their synthesis as hybrid proteins fused to the C terminus of endogenous amine oxidase. The hybrid genes, placed under control of the H. polymorpha alcohol oxidase promoter (PAOX were integrated into the genomic alcohol oxidase locus, yielding stable production strains. High-level synthesis of the fusion proteins, exceeding 20% of total cellular protein, was obtained when the transformed strains were grown in methanol-limited chemostat cultures; when expressed by itself, i.e. in the absence of the amine oxidase gene, IGF-II could not be recovered from crude cell extracts, probably as a result of rapid proteolytic degradation. Accumulation in peroxisomes did not significantly affect the IGF-II protein stability when expressed in the absence of the carrier protein. Apparently, fusion to the large (±78 kDa) amine oxidase carrier particularly stabilizes the peptides and prevents them from proteolysis. After partial purification, the fusion partners were readily separated by factor Xa treatment.