Structure of Methylobacterium extorquens malyl-CoA lyase: CoA-substrate binding correlates with domain shift

Malyl-CoA lyase (MCL) is an Mg2+-dependent enzyme that catalyzes the reversible cleavage of (2S)-4-malyl-CoA to yield acetyl-CoA and glyoxylate. MCL enzymes, which are found in a variety of bacteria, are members of the citrate lyase-like family and are involved in the assimilation of one- and two-carbon compounds. Here, the 1.56   Å resolution X-ray crystal structure of MCL from Methylobacterium extorquens AM1 with bound Mg2+ is presented. Structural alignment with the closely related Rhodobacter sphaeroides malyl-CoA lyase complexed with Mg2+, oxalate and CoA allows a detailed analysis of the domain motion of the enzyme caused by substrate binding. Alignment of the structures shows that a simple hinge motion centered on the conserved residues Phe268 and Thr269 moves the C-terminal domain by about 30 ° relative to the rest of the molecule. This domain motion positions a conserved aspartate residue located in the C-terminal domain in the active site of the adjacent monomer, which may serve as a general acid/base in the catalytic mechanism.

Source: Acta Crystallographica Section F - January 26, 2017 Category: Biochemistry Authors: Gonz á lez, J.M. Marti-Arbona, R. Chen, J.C.-H. Unkefer, C.J. Tags: biofuels metabolic engineering methanol malyl-CoA lyase Methylobacterium extorquens research communications Source Type: research