Amino Acids in the RSSY Motif of Lipoyl Synthase Control Substrate Binding and Reactivity
This study demonstrates that the Arg306 and Ser308 residues within the conserved RSSY motif of lipoyl synthase are critical for substrate binding and catalytic reactivity, with the S308C mutation specifically altering the auxiliary cluster's fate to produce a high-spin monothiolated intermediate and a desaturated byproduct instead of the normal lipoyl cofactor.