FIGURE 1.

Domain organization and cDNA construct for expression of C7 mutants. The 2944-amino acid sequence of C7 consists of a central triplehelical domain (TH) flanked by a large amino-terminal noncollagenous domain, NC1, and a smaller carboxyl-terminal noncollagenous domain, NC2. The triple-helical domain contains a non-collagenous 39-amino acid hinge region (HR) which is more sensitive to protease digestion. Four mutant C7 proteins (G2569R, G2575R, G2049E, and R2063W) generated by site-directed mutagenesis are shown in the schematic with the approximate positions of mutation indicated by the arrow. WT, wild type.