title: The covalent structure of collagen. The amino-acid sequence of alpha2-CB4 from calf-skin collagen.
abstract: Sequencing of chymotrypsin, trypsin, collagenase- and hydroxylamine-derived peptides, using the automated Edman degradation procedure, yielded the complete amino acid sequence of alpha2-CB4 from calf skin collagen (321 residues). Together with the data from earlier work, an uninterrupted sequence in the helical region of the alpha2-chain from residues 1-393 is now known. Glycine is found in every third position of the peptide. Hydroxylation of proline and lysine occurs only in the Y-position of the triplet Gly-X-Y and is not complete in every position. Some residues, such as glutamic acid, leucine, phenylalanine and arginine, are distributed non-randomly between the X and Y-positions and this non-random distribution is different in the alpha1 and alpha2-chains. Comparison of the N-terminal 393 residues from the helical region of the alpha1 and alpha2-chains revealed a nearly identical distribution of charged polar residues arginine, lysine, glutamic and aspartic acids. The distribution of the triplet Gly-Pro-Hyp is simialr in both chains. The remaining residues in the alpha2-chain exhibit a high degree of substitutions when compared with those in the alpha1-chain. Approximately one in every two residues in both the X and Y-positions are substituted.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D002918:Chymotrypsin; D003094:Collagen / Q000032:analysis*; D006898:Hydroxylamines; D003012:Microbial Collagenase; D010446:Peptide Fragments / Q000032:analysis; D011487:Protein Conformation; D012867:Skin / Q000032:analysis*; D014357:Trypsin
chemical_list: D000596:Amino Acids; D006898:Hydroxylamines; D010446:Peptide Fragments; D003094:Collagen; D002918:Chymotrypsin; D014357:Trypsin; D003012:Microbial Collagenase