Construction and characterization of cDNA encoding the .alpha.2 chain of chicken type IX collagen

Publisher Website
Google Scholar
Abstract
A cDNA encoding the carboxy-terminal half of 1 of the polypeptide subunits of a novel disulfide-bonded collagen found in hyaline cartilage was isolated and characterized. This collagen has been given the type assignment type IX, and it has several unusual characteristics. First, the polypeptide subunits are shorter than .alpha.-chains of the fibrillar collagens types I, II, and III. Second, type IX molecules are heterotrimers of 3 genetically distinct polypeptide subunits. Third, type IX molecules contain 3 triple-helical collagenous domains interspersed with noncollagenous domains. When chicken cartilage collagens are extracted with pepsin, type IX collagen is cleaved and gives rise to the triple-helical fragments HWM (high molecular weight) and LMW (low molecular weight). The identification of the cDNA reported here is based on a comparison of the amino acid composition of tryptic peptides derived from LMW with the composition of tryptic peptides predicted from the nucleotide sequence of the cDNA. The amino-terminal sequence of 1 of the subunits of LMW is identical with the sequence predicted from the nucleotide sequence of the cDNA. The amino-terminal amino acid sequence of a tryptic peptide isolated from 1 of the subunits of HMW is identical with a sequence predicted from the cDNA. The polypeptide chain encoded by the cDNA reported here is named .alpha.2(IX), and it is homologous to the .alpha.1(IX) chain.

This publication has 15 references indexed in Scilit: