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Mapping the Effect of Gly Mutations in Collagen on α2β1 Integrin Binding.

Published version
Peer-reviewed

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Authors

Yigit, Sezin 
Yu, Hongtao 
An, Bo 
Hamaia, Samir 
Farndale, Richard W 

Abstract

The replacement of one Gly in the essential repeating tripeptide sequence of the type I collagen triple helix results in the dominant hereditary bone disorder osteogenesis imperfecta. The mechanism leading to pathology likely involves misfolding and autophagy, although it has been hypothesized that some mutations interfere with known collagen interactions. Here, the effect of Gly replacements within and nearby the integrin binding GFPGER sequence was investigated using a recombinant bacterial collagen system. When a six-triplet human type I collagen sequence containing GFPGER was introduced into a bacterial collagen-like protein, this chimeric protein bound to integrin. Constructs with Gly to Ser substitutions within and nearby the inserted human sequence still formed a trypsin-resistant triple helix, suggesting a small local conformational perturbation. Gly to Ser mutations within the two Gly residues in the essential GFPGER sequence prevented integrin binding and cell attachment as predicted from molecular dynamics studies of the complex. Replacement of Gly residues C-terminal to GFPGER did not affect integrin binding. In contrast, Gly replacements N-terminal to the GFPGER sequence, up to four triplets away, decreased integrin binding and cell adhesion. This pattern suggests either an involvement of the triplets N-terminal to GFPGER in initial binding or a propagation of the perturbation of the triple helix C-terminal to a mutation site. The asymmetry in biological consequences relative to the mutation site may relate to the observed pattern of osteogenesis imperfecta mutations near the integrin binding site.

Description

Keywords

binding, collagen, extracellular matrix, integrin, missense mutations, molecular dynamics, osteogenesis imperfecta, recombinant protein expression, triple helix, Amino Acid Substitution, Collagen Type I, Humans, Integrin alpha2beta1, Mutation, Missense, Protein Binding, Protein Structure, Secondary

Journal Title

J Biol Chem

Conference Name

Journal ISSN

0021-9258
1083-351X

Volume Title

291

Publisher

Elsevier BV
Sponsorship
Medical Research Council (G0500707)
British Heart Foundation (RG/15/4/31268)
British Heart Foundation (None)
British Heart Foundation (None)
National Institutes of Health (Grant IDs: EB011620, GM60048), British Heart Foundation (Grant IDs: RG/15/4/31268, PG/10/011/28199), Tufts start-up fund, Knez Family Faculty Investment Fund