Indirect role of Ca2+ in the assembly of extracellular matrix proteins.

ABSTRACT: We have investigated through molecular dynamics the binding properties at the interface between the C-type lectin subdomain (CLD) of aggrecan and the fibronectin type III domains ((4-5)FnIII) of tenasin, in particular the mechanistically unknown, but essential role of Ca(2+) in the binding. The binding between the CLD and (4-5)FnIII is critical in cross-linking aggrecan, hyaluronan, and tenascin to form extended protein networks found in tissues such as cartilage. None of the structurally resolved Ca(2+) ions in the complex of the CLD and (4-5)FnIII is directly bridging the two proteins. However, one of the Ca(2+) ions (Ca2) is found to play the role of maintaining the structure of the L4 loop at the CLD binding surface, thus facilitating a high affinity binding between the CLD and (4-5)Fn

SUBMITTER: Diao J 

PROVIDER: S-EPMC2426659 | biostudies-literature | 2008 Jul

REPOSITORIES: biostudies-literature