Int. J. Mol. Sci. 2012, 13(12), 16899-16915; doi:10.3390/ijms131216899

Electrochemical Characterization of Escherichia coli Adaptive Response Protein AidB

1,2email, 2email, 2,†email, 1email, 2,3,4,5email and 1,* email
Received: 7 October 2012; in revised form: 26 November 2012 / Accepted: 3 December 2012 / Published: 11 December 2012
(This article belongs to the Special Issue Flavins)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: When exposed to known DNA-damaging alkylating agents, Escherichia coli cells increase production of four DNA repair enzymes: Ada, AlkA, AlkB, and AidB. The role of three enzymes (Ada, AlkA, and AlkB) in repairing DNA lesions has been well characterized, while the function of AidB is poorly understood. AidB has a distinct cofactor that is potentially related to the elusive role of AidB in adaptive response: a redox active flavin adenine dinucleotide (FAD). In this study, we report the thermodynamic redox properties of the AidB flavin for the first time, both for free protein and in the presence of potential substrates. We find that the midpoint reduction potential of the AidB flavin is within a biologically relevant window for redox chemistry at −181 mV, that AidB significantly stabilizes the flavin semiquinone, and that small molecule binding perturbs the observed reduction potential. Our electrochemical results combined with structural analysis allow for fresh comparisons between AidB and the homologous acyl-coenzyme A dehydrogenase (ACAD) family of enzymes. AidB exhibits several discrepancies from ACADs that suggest a novel catalytic mechanism distinct from that of the ACAD family enzymes.
Keywords: adaptive response; DNA repair; protein electrochemistry; acyl-coenzyme A dehydrogenase; flavin cofactor; reduction potential
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MDPI and ACS Style

Hamill, M.J.; Jost, M.; Wong, C.; Bene, N.C.; Drennan, C.L.; Elliott, S.J. Electrochemical Characterization of Escherichia coli Adaptive Response Protein AidB. Int. J. Mol. Sci. 2012, 13, 16899-16915.

AMA Style

Hamill MJ, Jost M, Wong C, Bene NC, Drennan CL, Elliott SJ. Electrochemical Characterization of Escherichia coli Adaptive Response Protein AidB. International Journal of Molecular Sciences. 2012; 13(12):16899-16915.

Chicago/Turabian Style

Hamill, Michael J.; Jost, Marco; Wong, Cintyu; Bene, Nicholas C.; Drennan, Catherine L.; Elliott, Sean J. 2012. "Electrochemical Characterization of Escherichia coli Adaptive Response Protein AidB." Int. J. Mol. Sci. 13, no. 12: 16899-16915.

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