The 3-Methylcrotonyl-CoA Carboxylase (MCC) Project

3-Methylcrotonyl-CoA carboxylase (MCC) catalyzes the biotin-dependent carboxylation of 3-methylcrotonyl-CoA. MCC is essential for the catabolism of the amino acid leucine. In Pseudomonas organisms, MCC is also involved in the metabolism of terpenoids.

Deficiencies of MCC activity in humans are linked to the disease methylcrotonylglycinuria (MCG) and other diseases. MCC deficiency is one of the most common metabolic disorders.

MCC holoenzyme is a 750-kD a6b6 dodecamer. The a subunit is known to contain the biotin carboxylase (BC) and biotin carboxyl carrier protein (BCCP) domains, and the b subunit supplies the carboxyltransferase (CT) activity.

MCC has strong sequence conservation with PCC (42 and 34% sequence identity for the a and b subunits, respectively). Both are 750-kD a6b6 dedecamers, and both are metabolic enzymes functioning in the mitochondrial matrix.

One difference between MCC and PCC is the site of carboxylation in the substrate. PCC carboxylates the a carbon of the organic acid (esterified to CoA), while MCC is active towards the g carbon of an a-b unsaturated acid.

Major findings from this project

Publications from this project

Funding for this project

© copyright 2012-2017, Liang Tong.