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Free keywords:
synthetic heterotrimers; collagen type IV; chain register; thermal stability; conformation
Abstract:
Collagen type IV is a highly specialized form of collagen found only in basement membranes, where it provides mechanical stability and structural integrity to tissues and organs, and binding sites for cell adhesion. In its ubiquitous form, collagen type IV consists of two alpha1 chains and one alpha2 chain, whose internal alignment within the triple helix seems to exert a strong influence on the binding affinity to alpha1beta1 integrin receptor. This has been assessed recently using two synthetic collagen peptides that contain the cell adhesion epitope of collagen type IV and are assembled into the most plausible alpha1alpha2alpha1' and alpha2alpha1alpha1' registers. In the present study, the effects of the chain register on the stability of the triple helix and the folding kinetics of these collagen peptides were investigated by CD spectroscopy and microcalorimetry. The results revealed a multidomain structural organization for both trimers, with an unexpected strong effect of the chain alignment on the conformational stability. Molecular dynamics simulations served to rationalize more properly the experimental results. (C) 2002 Elsevier Science Ltd. All rights reserved.
