Showing papers on "Peptide sequence published in 1972"

Primary structure effects on peptide group hydrogen exchange.

Abstract: The rate of exchange of peptide group NH hydrogens with the hydrogens of aqueous solvent is sensitive to neighboring side chains. To evaluate the effects of protein side chains, all 20 naturally occurring amino acids were studied using dipeptide models. Both inductive and steric blocking effects are apparent. The additivity of nearest-neighbor blocking and inductive effects was tested in oligo- and polypeptides and, surprisingly, confirmed. Reference rates for alanine-containing peptides were determined and effects of temperature considered. These results provide the information necessary to evaluate measured protein NH to ND exchange rates by comparing them with rates to be expected for the same amino acid sequence is unstructured oligo- and polypeptides. The application of this approach to protein studies is discussed.

Staphylococcal Protease: A Proteolytic Enzyme Specific for Glutamoyl Bonds

Abstract: An extracellular protease of Staphylococcus aureus, strain V8, previously shown to cleave specifically the peptide bonds on the carboxyl-terminal side of either aspartate or glutamate residues in phosphate buffer (pH 7.8) hydrolyzes only glutamoyl bonds in either ammonium bicarbonate (pH 7.8) or ammonium acetate (pH 4.0). Of all aspartoyl bonds tested, only the Asp-Gly linkage is cleaved at a detectable rate. The staphylococcal protease hydrolyzes all of the seventeen different glutamoyl bonds studied, although those involving hydrophobic aminoacid residues with bulky side chains are cleaved at a lower rate.

The Amino Acid Sequence of a Major Nonimmunoglobulin Component of Some Amyloid Fibrils

Abstract: A B S T R A C T The coxnplete amino acid sequence of a protein, acid soluble fraction, (ASF) which constitutes up to 50% of amyloid fibrils from a patient with familial Mediterranean fever has been obtained. Partial amino acid sequences of three other proteins from patients with secondary amyloidosis were identical in the regions studied except for an alanine-valine interchange in one. The ASF contains no cysteine, does not resemble any known immunoglobulin, and has not been detected as yet in myeloma-associated amyloid.

Amino Acid Sequence of Human apoLp-Gln-II (apoA-II), an Apolipoprotein Isolated from the High-Density Lipoprotein Complex

Abstract: An apolipoprotein, designated by its carboxyl-terminal residue as apoLp-Gln-II, has been isolated from the human high-density lipoprotein family, and its complete aminoacid sequence was determined. The apoprotein, one of the two major apoproteins of this family, is composed of two identical polypeptide chains, each containing 77 amino acids. The two polypeptide chains are connected by a single disulfide bridge at position 6 in the sequence. The minimum molecular weight of the intact apoprotein is 17,380. The amino-terminal residue of each chain is pyrrolidone carboxylic acid, and the carboxyl-terminal residue is glutamine.

Nerve Growth Factor and Insulin

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Amino-acid sequence of thermolysin.

Abstract: The following three articles describe how chemical and X-ray analyses have been combined to elucidate the structure of thermolysin. This first article describes the determination of the amino-acid sequence of this metalloendopeptidase.

Initiation of protein synthesis at an unusual position in an immunoglobulin gene

Abstract: The amino acid sequence of urinary beta(2)-microglobulin has been partially determined and found to be related to the constant region of IgG immunoglobulin heavy chain. beta(2)-Microglobulin is present in normal individuals. Its gene may have evolved from an immunoglobulin gene by the use of an unusually located start signal for initiating synthesis of the polypeptide.

Amino-acid sequence of rabbit skeletal tropomyosin and its coiled-coil structure.

Abstract: A tentative amino-acid sequence for the COOH-terminal half of rabbit skeletal tropomyosin is reported. These studies confirm our previous conclusions that this tropomyosin consists of several different but similar polypeptide chains. In the sequence, nonpolar residues occur in two series at intervals of seven residues. Amino-acid residues in series I are three residues on the NH2-terminal side of, and four residues on the COOH-terminal side of, residues in series II. The presence of occasional charged or ambivalent residues in the positions of series I or II does not lead to a disruption of this long-range pattern. The majority of residues located between the nonpolar residues are charged or polar amino acids. Two highly similar or identical α-helices with the reported sequence can be packed together in parallel in a coiled-coil structure. These may be in register or staggered by seven residues or some multiple of it. The observation that groups of small hydrophobic side chains appear to alternate with groups of bulky side chains suggests that a staggered arrangement of the two α-helices would maximize the regularity and hydrophobic interactions of the coiled-coil. Model building considerations show that this would occur with a stagger of 14 residues. Such an arrangement could account for the end-to-end aggregation of tropomyosin in solution, and in crystal and tactoid filaments. However, a structure in which the two polypeptides are in register cannot be ruled out.

Relationship between Bitterness of Peptides and their Chemical Structures

Abstract: Various peptides and derivatives of peptides and amino acids were synthesized and tasted, systematically, to elucidate the relationship between bitterness and chemical structures of peptidesWe have found that: 1 Peptides become more bitter than the original amino acids when their amino and carboxyl groups are blocked and when peptide bond is formed 2 A peptide molecule with a high content of amino acids with hydrophobic side chains will develop bitter taste 3 The amino acids in a peptide chain independently contribute to bitterness regardless of amino acid sequences and configuration

[14] Maleylation of amino groups.

Abstract: Publisher Summary Maleylation of the lysyl residues allows specific cleavage by trypsin at the arginyl bonds. The maleyl amino group is very stable at alkaline pH and is therefore unlikely to hydrolyze during prolonged enzymatic digestions at alkaline pH, a hazard inherent in alternative reversible blocking groups such as trifluoroacetyl-, or tetraftuorosuecinyl-, which are alkali labile. Cleavage at some arginyl residues in maleylated proteins seems to occur much more slowly than at others, probably because of inhibition by adjacent negative charges, and this kinetic specificity can be an advantage in obtaining large peptides for sequence studies. The maleyl group can, of course, be removed from each peptide by acid incubation to allow further tryptic cleavage at lysine residues. The charge change of +2 consequent on such unblocking is the basis of a diagonal electrophoretic separation which allows N-terminal and lysine-containing peptides to be specifically purified from enzymatic digests.

50-S Ribsomal Proteins

Abstract: Peptide studies on two acidic proteins, A1 and A2, from 50-S ribosomes of Escherichia coli indicate a closely related primary structure. 1 Amino acid compositions of the tryptic peptides of the two proteins are identical, with exception of the amino terminal peptide. 2 The N-terminal amino acid sequence of A2-protein is Ser-Ile-Thr-Lys, while that of A1-protein is N-acetyl-Ser-Ile-Thr-Lys. 3 The estimated number of 120 amino acid residues in each polypeptide chain is consistent with the physical molecular weight estimate. 4 In 50% of the polpeptide chains, in both A1 or A2-protein, a specific lysine residue is replaced by ɛ-N-monomethyl-lysine.

Gene triplication deduced from the tertiary structure of a muscle calcium binding protein.

Abstract: GENE duplication was first observed cytologically in the bar gene of drosophila1. The idea, extended by Dixon2, has been used to explain the obvious repeats in amino-acid sequence in the immunoglobulins, in bacterial ferredoxins, in haptoglobin α-2 (summarized in ref. 3) and in neurophysin4.

Sequence of the Murein · Lipoprotein and the Attachment Site of the Lipid

Abstract: The primary structure of a covalent lipoglycoprotein (murein · lipoprotein) from the cell wall of Escherichia coli is presented. The amino acid sequence consists of 57 residues. The lipid is attached to the N-terminal serine and the murein is bound to the 6-amino group of the C-terminal lysine of the lipoprotein. The repetitive design of the sequence suggests a very conservative evolution in which a structural gene coding for 15 amino acids was duplicated once and then only half of this gene, thus coding for 7 amino acids was fused four times with the first 29 amino acids. Some deletions but only few exchanges of amino acids apparently occurred. This structural membrane lipoprotein aggregates strongly when released from the murein by lysozyme digestion. The molecular weight was therefore determined in 2%, 0.5% and 0.1% dodecylsulfate by polyacrylamide gel electrophoresis and gel chromatography. The molecular weight of 13000 thus found deviated from that of 10000 calculated from the sum of the amino acids, the lipid as known so far and the part of the murein remaining bound to the lipoprotein. This was not due to a different amount of dodecylsulfate binding by the lipoprotein compared with proteins containing no lipid but may be due to a more spherical shape of the small molecule in contrast to the rod-like shape of standard proteins in dodecylsulfate.

The complete amino acid sequence of a mouse kappa light chain.

Abstract: The complete amino acid sequence of the kappa-chain of the mouse myeloma protein MOPC 21 was established. The protein was reduced and alkylated with iodo[2-(14)C]acetic acid, and 21 tryptic peptides were isolated, mainly by paper electrophoresis and paper chromatography. Three large tryptic peptides (of 35, 36 and 42 residues), which were difficult to isolate in this manner, were obtained pure and in excellent yields by a combination of Sephadex G-50 gel filtration in 1% (w/v) NH(4)HCO(3) and chromatography on a DEAE-cellulose column in ammonium acetate buffer, pH8.1. Peptides overlapping the tryptic peptides were isolated from a chymotryptic digest. The chain is 214 residues long. Microheterogeneity of two peptides was observed and is believed to be due to deamidation. It was not excluded that such deamidation could occur in serum from which the protein was isolated. The sequence is compared with the sequences of two other mouse kappa-chains, and with the human kappa-chain basic sequences.

Repetitive Sequences in the Murein-Lipoprotein of the Cell Wall of Escherichia coli

Abstract: The amino-acid sequence of the murein-lipoprotein of the Escherichia coli cell wall is presented. This protein is covalently bound to a lipid component as well as to the murein (peptidoglycan, mucopeptide). The sequence is also highly repetitive. At the N-terminal portion, there are three adjacent almost identical sequences, indicating repeated duplication of a gene coding originally for 15 amino acids. The C-terminal part of the polypeptide chain is more variable but still shows striking homology when certain sequence gaps are introduced. The lipid is bound to the N-terminal serine of the dipeptide (Ser-Ser) that extends from the repetitive sequence. At the C-terminal end where the murein is bound, a tripeptide extends from the repetitive portion. Here there are several basic amino acids and the only aromatic amino acid in the lipoprotein. The sequence is Lys-Tyr-Arg-Lys. The linkage to the murein is formed between the e-amino group of the C-terminal lysine and the carboxyl group of the optical L-center of meso-diaminopimelic acid. The polypeptide chain is composed of 57 amino acids and lacks glycine, proline, cysteine, phenylalanine, histidine, and tryptophan. 63% of the amino acids are hydrophilic, but because of the covalently linked lipid this structural membrane protein has very hydrophobic properties.

The amino acid sequence of γ-crystallin (fraction II) from calf lens

Abstract: The amino acid sequence of γ-crystallin (fraction II) from calf lens has been determined; this indicates it to be a single-chain polypeptide of 165 amino acid residues.