Many food plants accumulate oxalate, which humans absorb but do not metabolize, leading to the formation of urinary stones. The commensal bacterium Oxalobacter formigenes consumes oxalate by converting it to oxalyl- CoA, which is decarboxylated by oxalyl-CoA decarboxylase (OXC). OXC and the class III CoA-transferase formyl- CoA:oxalate CoA-transferase (FCOCT) are widespread among bacteria, including many that have no apparent ability to degrade or to resist external oxalate. The EvgA acid response regulator activates transcription of the Escherichia coli yfdXWUVE operon encoding YfdW (FCOCT), YfdU (OXC), and YfdE, a class III CoA-transferase that is ~ 30% identical to YfdW. YfdW and YfdU are necessary and sufficient for oxalate-induced protection against a subsequent acid challenge; neither of the other genes has a known function. We report the purification, in vitro characterization, 2.1-A crystal structure, and functional assignment of YfdE. YfdE and UctC, an orthologue fromthe obligate aerobe Acetobacter aceti, perform the reversible conversion of acetyl- CoA and oxalate to oxalyl-CoA and acetate. The annotation of YfdE as acetyl-CoA:oxalate CoA-transferase (ACOCT) expands the scope of metabolic pathways linked to oxalate catabolism and the oxalate-induced acid tolerance response. FCOCT and ACOCT active sites contain distinctive, conserved active site loops (the glycine-rich loop and the GNxH loop, respectively) that appear to encode substrate specificity.


This is the author accepted version of Mullins EA, Sullivan KL, Kappock TJ (2013) Function and X-Ray crystal structure of Escherichia coli YfdE. PLoS ONE 8(7): e67901. doi:10.1371/journal.pone.0067901.

Copyright 2013 Mullins et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This work was supported by National Science Foundation grant MCB 0936108 and Purdue University Agricultural Research Programs. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


centrifugation, crystal structure, formates, oxalates, sequence alignment

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Supporting information for: Function and X-ray crystal structure of Escherichia coli YfdE

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