National Center for
4G2R: Crystal Structure Of The Carboxyltransferase Subunit Of Acc (accd6) In Complex With Inhibitor Haloxyfop From Mycobacterium Tuberculosis
Structure, Activity, and Inhibition of the Carboxyltransferase beta-subunit of Acetyl-CoA Carboxylase (AccD6) from Mycobacterium tuberculosis
Antimicrob. Agents Chemother. (2014)
In Mycobacterium tuberculosis (Mtb) the carboxylation of acetyl-CoA to produce malonyl-CoA, a building block in long chain fatty acid biosynthesis, is catalyzed by two enzymes working sequentially: a biotin carboxylase (AccA), and a carboxyltransferase (AccD). While the exact roles of the three different biotin carboxylases (AccA1-3) and the six carboxyltransferases (AccD1-6) in Mtb are still not clear, AccD6 in complex with AccA3 can synthesize malonyl-CoA from acetyl-CoA. A series of ten herbicides that target plant acetyl-CoA carboxylases (ACC) were tested for inhibition of AccD6 and for whole-cell activity against Mtb. From the tested herbicides, haloxyfop, an arylophenoxypropionate, showed in vitro inhibition of Mtb AccD6, with an IC50 = 21.4 +/- 1 muM. Here, we report the crystal structures of Mtb AccD6 in the apo form (3.0 A) and in complex with haloxyfop-R (2.3 A). The structure of Mtb AccD6 in complex with haloxyfop-R shows two molecules of the inhibitor bound on each AccD6 subunit. These results represent the potential for developing novel therapeutics for tuberculosis based on herbicides with low human toxicity.