1ei8
|
STRUCTURAL CONSEQUENCES OF A DISCONTINUITY IN THE REPEATING TRIPEPTIDE SEQUENCE OF A COLLAGEN-LIKE TRIPLE-HELICAL PEPTIDE
OverviewOverview
The collagen model peptide with sequence (Pro-Hyp-Gly)4-Pro-Gly-(Pro-Hyp-Gly)5 contains a central Gly-Pro-Gly interruption in the consensus collagen sequence. Its high-resolution crystal structure defines the molecular consequences of such an interruption for the collagen triple-helical conformation, and provides insight into possible structural and biological roles of similar interruptions in the -Gly-X-Y- repeating pattern found in non-fibrillar collagens. The peptide (denoted as the Hyp minus peptide or Hyp-) forms a rod-like triple helix structure without any bend or kink, and crystallizes in a quasi-hexagonal lattice. The two Pro-Hyp-Gly zones adopt the typical triple-helical collagen conformation with standard Rich and Crick II hydrogen bonding topology. Notably, the central zone containing the Gly-Pro-Gly interruption deviates from the standard structure in terms of hydrogen bonding topology, torsion angles, helical, and superhelical parameters. These deviations are highly localized, such that the standard features are regained within one to two residues on either side. Conformational variations and high temperature factors seen for the six chains of the asymmetric unit in the zone around the interruption point to the presence of a local region of considerable plasticity and flexibility embedded within two highly rigid and ordered standard triple-helical segments. The structure suggests a role for Gly-X-Gly interruptions as defining regions of flexibility and molecular recognition in the otherwise relatively uniform repeating collagen conformation.
About this StructureAbout this Structure
1EI8 is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
ReferenceReference
Conformational effects of Gly-X-Gly interruptions in the collagen triple helix., Bella J, Liu J, Kramer R, Brodsky B, Berman HM, J Mol Biol. 2006 Sep 15;362(2):298-311. Epub 2006 Jul 15. PMID:16919298
Page seeded by OCA on Thu Feb 21 12:28:00 2008