[Changes in the structure of type I collagen and cross-links between type I and type III collagen chains in a patient with funnel chest].

: Skin and rib cartilage collagens were studied in patient 1.I.K. with isolated form of pigeon chest as well as in a group of children without any impairments of connective tissue. Distinct decrease in stability of collagen I, an increase in the ration of alpha 1 (I)/alpha 2(I) chains and impairment in formation of beta 12 dimers were detected in the patient with pigeon chest. In the patient skin total ratio between collagens I and III, calculated from a content of BrCN-peptides, was similar to normal level, whereas the proportion was markedly increased between intact molecules of collagens III and I free of cross-links, which was calculated from the ratio of alpha 1(III)/alpha 2(I) chains. Presence of cross-links between alpha 1 (III) and alpha 2 (I) chains as well as between alpha 1 (III) and alpha 2 (I) chains was detected after peptide mapping of polypeptides arranged in the region of beta 11 and beta 12 dimers. All the collagen I preparation, extracted from skin of the patient 1.I.K., contained molecules with unstabilized N-terminal sites. These results suggest that mutation occurred in the N-terminal region of alpha 1(I) chain. Analysis of collagen from the patient 1.I.K. rib cartilage demonstrated a slight decrease in total stability of collagen II as well as elevated concentration of collagen II molecules containing unstabilized N-terminals. Mechanisms responsible for formation of cross-links between polypeptide chains of collagens I and III detected in human skin are discussed.