Hydration structure of a collagen peptide
Research ArticleHydration structure of a collagen peptide Author links open overlay panel, , Open archive Abstract Background: The collagen triple helix is a unique protein motif defined by the supercoiling of three polypeptide chains in a polyproline II confo
Research Article
Hydration structure of a collagen peptideOpen archive
Abstract
Background: The collagen triple helix is a unique protein motif defined by the supercoiling of three polypeptide chains in a polyproline II conformation. It is a major domain of all collagen proteins and is also reported to exist in proteins with host defense function and in several membrane proteins. The triple-helical domain has distinctive properties. Collagen requires a high proportion of the post-translationally modified imino acid 4-hydroxyproline and water to stabilize its conformation and assembly. The crystal structure of a collagen-like peptide determined to 1.85 å showed that these two features may be related.
Results A detailed analysis of the hydration structure of the collagen-like peptide is presented. The water molecules around the carbonyl and hydroxyprolyl groups show distinctive geometries. There are repetitive patterns of water bridges that link oxygen atoms within a single peptide chain, between different chains and between different triple helices. Overall, the water molecules are organized in a semi-clathrate-like structure that surrounds and interconnects triple helices in the crystal lattice. Hydroxyprolyl groups play a crucial role in the assembly.
Conclusion The roles of hydroxyproline and hydration are strongly interrelated in the structure of the collagen triple helix. The specific, repetitive water bridges observed in this structure buttress the triple-helical conformation. The extensively ordered hydration structure offers a good model for the interpretation of the experimental results on collagen stability and assembly.
Keywords
collagen
hydration
hydroxyproline
triple helix
water bridges
Jordi Bella and Helen M Berman (corresponding author), Department of Chemistry, Rutgers University, Piscataway, NJ 08855, USA.
Barbara Brodsky, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
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