The α1 Chain of Collagen XI, Posttranslational Modifications, and the Pericellular Matrix

Collagen type XI is a quantitatively minor but developmentally essential component of the extracellular matrix and as a secreted protein is subject to a variety of posttranslational modifications. These modifications have been shown to influence the affinity of endogenous binding between collagen XI and various extracellular matrix components. The three dimensional structure of the amino terminal domain (Npp) of this molecule has been determined through homology modeling. As a result a putative heparan sulfate binding site has been predicted. Heparan sulfate is an abundant sugar found on the surface of most cells and on proteoglycan molecules of the pericellular matrix. This study focuses on the structure of amino terminal domain of a1 of collagen type XI and the subsequent interactions between this domain and other extracellular matrix proteins.