Electrochemical Characterization of Escherichia coli Adaptive Response Protein AidB
Author(s)Hamill, Michael J.; Jost, Marco; Wong, Cintyu; Bene, Nicholas C.; Drennan, Catherine L.; Elliott, Sean J.; ... Show more Show less
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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.
Departmentmove to dc.description.sponsorship; Massachusetts Institute of Technology. Center for Environmental Health Sciences; Massachusetts Institute of Technology. Department of Biology; Massachusetts Institute of Technology. Department of Chemistry; Massachusetts Institute of Technology. School of Science
International Journal of Molecular Sciences
Hamill, Michael et al. “Electrochemical Characterization of Escherichia Coli Adaptive Response Protein AidB.” International Journal of Molecular Sciences 13.12 (2012): 16899–16915.
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