Sandbox Wabash 13

Distinguishing between the active site and a nearby dicarboxylic acid binding site in Fumarase

In early studies, two carboxylic acid binding sites, subsequently named A- and B-, were observed in the wild type crystal structure of fumarase C in E. Coli. The structures of these two sites was considerably different as site A contained atom of three of the four subunits of fumarase C whereas site B contained only atoms from a single subunit of the tetramer. While it was heavily believed that the carboxylic acid binding site A- was the location of the fumarase active site, it could not be verified without first mutating both active sites in order to determine the activity of the reactions ^[1]