Figure 1.

The human C3 protein sequence was retrieved from Genbank at the National Center for Biotechnology Information (NCBI) with the accession number AAA85332.1. To determine the potential impact of the selected C3 SNPs on the overall protein structure, we modeled the mutations in protein sequence with Modeller, and then visualized changes in the 3D protein structures of the two wild-type alleles using the VMD (v1.9.3) software. The color coding is as follows: a-helix=purple, 3_10 helix=blue, extended b=yellow, bridge b=turn, turn, cyan, and coil=white. Relative to the published C3 structure,^8,35 we observed that Arg>Gly¹⁰² mutation is located in the macroglobulin MG1domain, while the Gly>Asp¹²²⁴ is located on the TED.