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PDB:1BKV

Protein Name

Collagen like model peptide (T3-785 peptide)

Species

Synthetic peptide (containing human type III collagen sequence)

Biological Context

Collagen is a main component of connective tissues such as bone and cartilage, and the collagen fibril makes the tissues stiff and elastic. Collagen also forms an extracellular scaffold, extracellular matrix, where various proteins bind and regulate various physiological functions; integrin mediated contact signaling, collagenase induced chemotaxis, and so on.

Structure Description

1bkv1bkv_x1bkv_y

Three collagen peptides form a rod-like triple supercoil. The peptides require triplet repeat sequence containing glycine(Gly) every third residue, (X1-X2-Gly)n. X1 and X2 are most frequently imino acids Proline(Pro) and Hydroxyproline(Hyp) respectively, however how X1 and X2 residues affect the local structure of the helix was not fully understood. To address this question, Kramer et al. created T3-785 peptide, (Pro-Hyp-Gly)3-Ile-Thr-Gly-Ala-Arg-Gly-Leu-Ala-Gly-Pro-Hyp-Gly-(Pro-Hyp-Gly)3, as a collagen-like model peptide, which includes collagenase recognition sequence of human type III capped with (Pro-Hyp-Gly)3 in the N- and C-terminus. They compared the structure of coils between imino acid-rich N- and C- terminal and full amino acid collagenase recognition sequence. Their findings were following.

○ N- and C- terminal coils were 7-fold symmetry(fig1 A) while the middle coil was 10-fold symmetry(fig1 B).

○ In the middle coil, but not in N- and C- terminal coils, two types of hydrogen bond existed; (1)between N-H of Gly and O=C of X1, (2)between N-H of X1 and O=C of Gly mediated by a water molecule.

These results indicates that local conformational variation of collagen supercoil depends on the residue of X1 and X2, and may contribute to the formation of interaction domain to the wide range molecules.

fig1A fig1B N- and C- terminal 7-fold symmetric coil(left: fig1A) and middle 10-fold symmetric coil. Three different peptide chains are colored red, blue and green.

Protein Data Bank (PDB)

References

Source

Kramer, R.Z. Bella, J. Mayville, P. Brodsky, B. Berman, H.M.; "Sequence dependent conformational variations of collagen triple-helical structure."; Nature Struct. Biol.; (1999) 6:454-457 PubMed:10331873.

Others

author: Daisuke Ino


Japanese version:PDB:1BKV