Backbone assignments of the biotin carboxyl carrier protein domain of Propionyl CoA carboxylase of Leishmania major and its interaction with its cognate Biotin protein ligase.

Overview

Propionyl CoA carboxylase (PCC) is a multimeric enzyme composed of two types of subunits, α and β arranged in α₆β₆ stoichiometry. The α-subunit consists of an N-terminal carboxylase domain, a carboxyl transferase domains, and a C-terminal biotin carboxyl carrier protein domain (BCCP). The β-subunit is made up of an N- and a C- carboxyl transferase domain. During PCC catalysis, the BCCP domain plays a central role by transporting a carboxyl group from the α-subunit to the β-subunit, and finally to propionyl CoA carboxylase, resulting in the formation of methyl malonyl CoA. A point mutation in any of the subunits interferes with multimer assembly and function. Due to the association of this enzyme with propionic acidemia, a genetic metabolic disorder found in humans, PCC has become an enzyme of wide spread interest. Interestingly, unicellular eukaryotes like Leishmania also possess a PCC in their mitochondria that displays high sequence conservation with the human enzyme. Thus, to understand the function of this enzyme at the molecular level, we have initiated studies on Leishmania major PCC (LmPCC). Here we report chemical shift assignments of LmPCC BCCP domain using NMR. Conformational changes in LmPCC BCCP domain upon biotinylation, as well as upon interaction with its cognate biotinylating enzyme (Biotin protein ligase from L. major) have also been reported. Our studies disclose residues important for LmPCC BCCP interaction and function.