Gly-X-Y tripeptide frequencies in collagen: a context for host-guest triple-helical peptides.
The collagen triple-helix consists of a repeating (Gly-X-Y)n sequence. In theory, there are more than 400 possible Gly-X-Y triplets, but analysis of sequences from fibrillar and nonfibrillar collagens shows that only a limited set of triplets are found in significant numbers, and many are never observed. The nonrandom frequency of Gly-X-Y triplets makes it practical to experimentally approach the stability of much of the collagen sequence through the study of a limited set of host-guest peptides. In these peptides, individual Gly-X-Y triplets constitute the guest, while the host consists of Gly-Pro-Hyp tripeptides. A set of host-guest peptides was designed to contain the most common nonpolar and charged triplets found in collagen. All formed stable triple-helices, with their melting temperature depending on the identity of the guest triplet. While including less than 10% of all possible triplets, the data set covers 50-60% of collagen sequences and provides a starting point for establishing a stability scale to predict the relative stability of important collagen regions, such as the matrix metalloproteinase cleavage site or binding sites.
CSIRO Division of Molecular Science, Parkville, Victoria, 3052, Australia.
J A
JA
Ramshaw
N K
NK
Shah
B
B
Brodsky
D000595:Amino Acid Sequence; D000818:Animals; D003094:Collagen / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D011487:Protein Conformation
D003094:Collagen