MULTISTEP TRANSITIONS IN COLLAGENS

Citation
D. Kapoor et al., MULTISTEP TRANSITIONS IN COLLAGENS, Journal of macromolecular science. Physics, B37(6), 1998, pp. 723-746
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Polymer Sciences
ISSN journal
0022-2348
Volume
B37
Issue
6
Year of publication
1998
Pages
723 - 746
Database
ISI
SICI code
0022-2348(1998)B37:6<723:MTIC>2.0.ZU;2-K
Abstract
It is well known that collagens exist in triple-helical form, and, on average, the individual chains have glycine at every third place. Coll agens from different sources vary in distributions of other amino acid s. They could also be different in the distribution of defects, which are generally nonhelical regions of low stability. Varying lengths of individual chains in the triple-helical system can also contribute to this variability. All these variations manifest themselves in the crea tion of a transition profile with undulations that are indicative of a multiphasic nature. In the present communication, we try to understan d this variability by using essentially the Zimm and Bragg approach an d suitably amending it for a triple-helical system. Factors that contr ibute to the multiphasic nature are incorporated into the transition m odel and discussed. Results obtained for collagen types I, II, III, V- x, V-y, and XI are in agreement with the experimental measurements. Tr ansitions in the first three types can be interpreted on the basis of two-phase theory. Nucleation parameters, which are indicative of the s harpness of transition, are interpreted in terms of stability and poss ible amino acid composition.