Search

The first component (Elo) of the Escherirhia coil 2-oxoglutarate dehydrogenase complex (OGDHc) was engineered to accept substrates lacking the 5-carboxylate group by subjecting H260 and H298 to saturation mutagenesis. Apparently, H260 is required for substrate recognition, but H-298 could be replaced with hydrophobic residues of similar molecular volume. To interrogate whether the second component would allow synthesis of acyl-coenzyme A derivatives, hybrid complexes consisting of recombinant components of OGDHc (o) and pyruvate dehydrogenase (p) enzymes were constructed, suggesting that a different component is the "gatekeeper" for specificity for these two multienzyme complexes in bacteria' Elp foe pyruvate but E2o for 2-oxoglutarate. [ABSTRACT FROM AUTHOR]