The role of the lys628 (192) residue of the complement protease, c1s, in interacting with Peptide and protein substrates.

ABSTRACT: The C1s protease of the classical complement pathway propagates the initial activation of this pathway of the system by cleaving and thereby activating the C4 and C2 complement components. This facilitates the formation of the classical pathway C3 convertase (C4bC2a). C1s has a Lys residue located at position 628 (192 in chymotrypsin numbering) of the SP domain that has the potential to partially occlude the S2-S2' positions of the active site. The 192 residue of serine proteases generally plays an important role in interactions with substrates. We therefore investigated the role of Lys628 (192) in interactions with C4 by altering the Lys residue to either a Gln (found in many other serine proteases) or an Ala residue. The mutant enzymes had altered specificity profiles for a combinatorial

SUBMITTER: Wijeyewickrema LC 

PROVIDER: S-EPMC4166353 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature