Publication Date:
1994-10-07
Description:
The structure of a protein triple helix has been determined at 1.9 angstrom resolution by x-ray crystallographic studies of a collagen-like peptide containing a single substitution of the consensus sequence. This peptide adopts a triple-helical structure that confirms the basic features determined from fiber diffraction studies on collagen: supercoiling of polyproline II helices and interchain hydrogen bonding that follows the model II of Rich and Crick. In addition, the structure provides new information concerning the nature of this protein fold. Each triple helix is surrounded by a cylinder of hydration, with an extensive hydrogen bonding network between water molecules and peptide acceptor groups. Hydroxyproline residues have a critical role in this water network. The interaxial spacing of triple helices in the crystal is similar to that in collagen fibrils, and the water networks linking adjacent triple helices in the crystal structure are likely to be present in connective tissues. The breaking of the repeating (X-Y-Gly)n pattern by a Gly--〉Ala substitution results in a subtle alteration of the conformation, with a local untwisting of the triple helix. At the substitution site, direct interchain hydrogen bonds are replaced with interstitial water bridges between the peptide groups. Similar conformational changes may occur in Gly--〉X mutated collagens responsible for the diseases osteogenesis imperfecta, chondrodysplasias, and Ehlers-Danlos syndrome IV.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bella, J -- Eaton, M -- Brodsky, B -- Berman, H M -- AR 19626/AR/NIAMS NIH HHS/ -- GM 21589/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1994 Oct 7;266(5182):75-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Rutgers University, New Brunswick, NJ 08855.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7695699" target="_blank"〉PubMed〈/a〉
Keywords:
Alanine/chemistry
;
Amino Acid Sequence
;
Collagen/*chemistry
;
Computer Graphics
;
Crystallography, X-Ray
;
Glycine/chemistry
;
Hydrogen Bonding
;
Hydroxyproline/chemistry
;
Models, Molecular
;
Molecular Sequence Data
;
Molecular Structure
;
Peptides/*chemistry
;
*Protein Conformation
;
Protein Structure, Secondary
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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