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Antimicrobial peptides

About: Antimicrobial peptides is a research topic. Over the lifetime, 10645 publications have been published within this topic receiving 507688 citations. The topic is also known as: host defense peptide & antimicrobial protein.


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Journal ArticleDOI
TL;DR: This review focused on S. aureus virulence factors involved in the immune evasion in the first phases of infection: TLR recognition avoidance, adhesins affecting immune response and resistance to host defenses peptides and polypeptides.

202 citations

Journal ArticleDOI
TL;DR: Structural-activity modeling of the structural features determining the activity of tethered peptides indicated that the extent and positioning of positive charges and hydrophobic residues were influential in determining activity.

201 citations

Journal ArticleDOI
TL;DR: Hidden Markov models that enable recognition of individual classes of antimicrobials peptides with up to 99% accuracy and can be used for discovering novel AMP candidates are constructed.
Abstract: Motivation Increasing antibiotics resistance in human pathogens represents a pressing public health issue worldwide for which novel antibiotic therapies based on antimicrobial peptides (AMPs) may offer one possible solution. In the current study, we utilized publicly available data on AMPs to construct hidden Markov models (HMMs) that enable recognition of individual classes of antimicrobials peptides (such as defensins, cathelicidins, cecropins, etc.) with up to 99% accuracy and can be used for discovering novel AMP candidates. Results HMM models for both mature peptides and propeptides were constructed. A total of 146 models for mature peptides and 40 for propeptides have been developed for individual AMP classes. These were created by clustering and analyzing AMP sequences available in the public sources and by consequent iterative scanning of the Swiss-Prot database for previously unknown gene-coded AMPs. As a result, an additional 229 additional AMPs have been identified from Swiss-Prot, and all but 34 could be associated with known antimicrobial activities according to the literature. The final set of 1045 mature peptides and 253 propeptides have been organized into the open-source AMPer database. Availability The developed HMM-based tools and AMP sequences can be accessed through the AMPer resource at http://www.cnbi2.com/cgi-bin/amp.pl

201 citations

Journal ArticleDOI
TL;DR: The ird5 gene encodes a Drosophila homolog of mammalian IkappaB kinases (IKKs), and the phenotype and sequence suggest that the gene is specifically required for the activation of Relish, a Dosophila NF-kappaB family member.
Abstract: In both mammals and Drosophila, microbial infection activates Toll-like receptor (TLR) signaling pathways as a part of the innate host defense response (for review, see Anderson 2000). TLR-mediated signaling pathways are essential for appropriate responses to bacterial infection. In addition, mouse Tlr4 mediates septic shock associated with infection by gram-negative bacteria (Vogel 1992; Poltorak et al. 1998). The available data indicate that different microbial cell wall components activate different Toll-like receptor signaling pathways, which regulate distinct sets of target genes. In mammals, TLR4 is the prime mediator of responses to bacterial lipopolysaccharide, while TLR2 mediates responses to bacterial peptidoglycans (Poltorak et al. 1998; Takeuchi et al. 1999; for review, see Beutler 2000). The best-studied aspect of the Drosophila innate immune response is the rapid transcriptional induction of antimicrobial peptide genes in response to infection (Hultmark 1993; Hoffmann 1995). Infection by different classes of microorganisms leads to the preferential induction of particular subsets of antimicrobial peptides (Lemaitre et al. 1997), indicating that different microbial components activate different signaling pathways. At least two Toll-related signaling pathways are required for the activation of the Drosophila antimicrobial peptide genes. The Toll pathway itself, which was first identified because of its essential role in Drosophila embryonic patterning (Anderson et al. 1985), is essential for the induction of an antifungal peptide gene, drosomycin, although the antibacterial peptide genes are still induced in Toll pathway mutants (Lemaitre et al. 1996). Another Drosophila member of the Toll family, 18-wheeler, is required for the normal induction of attacin, an antibacterial peptide gene, but mutations in 18-wheeler do not prevent the induction of other antibacterial peptides (Williams et al. 1997). The imd gene is important for the induction of Diptericin and other antibacterial peptides (Lemaitre et al. 1995a; Corbo and Levine 1996) and, therefore, appears to be a component of a third signaling pathway activated by infection, but its biochemical function is not known. Each of the three Drosophila signaling pathways activated by infection leads to activation of NF-κB/Rel dimers, just as the mammalian TLRs activate NF-κB. All three Drosophila Rel proteins, Dorsal, Dif, and Relish, are expressed in the fat body cells that produce the antimicrobial peptides, and all three are activated within 30 min after infection by translocation from the cytoplasm to the nuclei (Ip at al. 1993; Lemaitre et al. 1995b; Stoven et al. 2000). Adults that lack Dif fail to induce Drosomycin, an antifungal peptide, and Defensin, which is active against gram-positive bacteria, but the other antimicrobial peptide genes are induced normally (Manfruelli et al. 1999; Meng et al. 1999; Rutschmann et al. 2000). Animals that lack Dorsal show normal induction of the antimicrobial peptide genes in response to infection (Lemaitre et al. 1995b), although Dorsal may act redundantly with Dif in larvae (Manfruelli et al. 1999; Rutschmann et al. 2000). Relish is a compound protein with an N-terminal Rel domain and a C-terminal IκB-like domain, similar to mammalian p100 and p105 (Dushay et al. 1996). Relish is activated by signal-dependent proteolysis, which liberates the N-terminal Rel domain, allowing it to translocate into nuclei (Stoven et al. 2000). Adults that lack Relish completely fail to induce the antibacterial peptides Diptericin and Cecropin and show reduced induction of the other antimicrobial peptides (Hedengren et al. 1999). The signaling pathway that activates Relish and controls induction of the antibacterial peptide genes has not been defined. We carried out a genetic screen to identify EMS-induced mutations on the Drosophila third chromosome that affect the antibacterial signaling pathway (Wu and Anderson 1998). A large number of mutants were identified and named ird (immune response deficient) mutants. This screen identified two alleles of the ird5 gene on the basis of the failure of homozygous mutant larvae to induce a diptericin-lacZ reporter gene in response to infection. Here we show that the ird5 gene is essential for antibacterial responses and encodes a Drosophila homolog of mammalian IκB kinases.

201 citations

Journal ArticleDOI
TL;DR: It is found that it is not important for antimicrobial and cytotoxic activity whether and how cysteine residues are arranged to form disulfide bonds, and the antimicrobial potency of hBD-3 peptides is determined by the distribution of positively charged amino acid residues and hydrophobic side chains.
Abstract: Human β-defensins form a group of cysteine-rich antimicrobial peptides which have been found in epithelial tissue and, more recently, in the male genital tract. They play a role in the defense against microbial pathogens in innate immunity and display additional chemotactic functions in the adaptive immune system. An important characteristic of antimicrobial peptides is that they also exhibit toxic potential on eukaryotic cells. Very little is known about the structure dependence of antimicrobial and cytotoxic effects. We investigated human β-defensin 3 (hBD-3), a potent broad-spectrum antimicrobial effector peptide, regarding the influence of structural parameters on the antimicrobial and cytotoxic activity. We have established a structure−activity relation of the hBD-3 using synthetic derivatives differing in length, charge, disulfide connectivity, and overall hydrophobicity. The antimicrobial activity of the peptides was compared to the cyctotoxic effects on monocytic THP-1 cells and the hemolytic acti...

201 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023512
20221,025
2021809
2020844
2019728
2018634