A subunit of pyruvate carboxylase. Biotin, covalently attached to the BCCP, transports CO2 from the BC active site to the PC active site of an adjacent subunit. (BC) biotin carboxylase; (BCCP) biotin carboxyl carrier protein; (PC) pyruvate carboxylase; (PT) pyruvate carboxylase tetramerization domain.
[Information from G. Lasso, L.P.C. Yu, D. Gil, S. Xiang, L. Tong, and M. Valle, Structure 18:1300–