1CAG

CRYSTAL AND MOLECULAR STRUCTURE OF A COLLAGEN-LIKE PEPTIDE AT 1.9 ANGSTROM RESOLUTION

Summary for 1CAG

• Entry DOI: 10.2210/pdb1cag/pdb
• Descriptor: COLLAGEN-LIKE PEPTIDE, ACETIC ACID (3 entities in total)
• Functional Keywords: collagen
• Total number of polymer chains: 3
• Total formula weight: 8474.87

Authors

Bella, J.,Eaton, M.,Brodsky, B.,Berman, H.M. (deposition date: 1994-03-29, release date: 1994-11-01, Last modification date: 2024-06-05)

Primary citation

Bella, J.,Eaton, M.,Brodsky, B.,Berman, H.M.
Crystal and molecular structure of a collagen-like peptide at 1.9 A resolution.
Science, 266:75-81, 1994

PubMed Abstract: 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.

PubMed: 7695699

Experimental method

X-RAY DIFFRACTION (1.85 Å)