Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/84711
Title: Redox chemistry of Mycobacterium tuberculosis alkylhydroperoxide reductase E (AhpE): Structural and mechanistic insight into a mycoredoxin-1 independent reductive pathway of AhpE via mycothiol
Authors: Kumar, Arvind
Balakrishna, Asha Manikkoth
Nartey, Wilson
Manimekalai, Malathy Sony Subramanian
Grüber, Gerhard
Keywords: AhpE
Alkyl hydroperoxide reductase
Issue Date: 2016
Source: Kumar, A., Balakrishna, A. M., Nartey, W., Manimekalai, M. S. S., & Grüber, G. (2016). Redox chemistry of Mycobacterium tuberculosis alkylhydroperoxide reductase E (AhpE): Structural and mechanistic insight into a mycoredoxin-1 independent reductive pathway of AhpE via mycothiol. Free Radical Biology and Medicine, 97, 588-601.
Series/Report no.: Free Radical Biology and Medicine
Abstract: Mycobacterium tuberculosis (Mtb) has the ability to persist within the human host for a long time in a dormant stage and re-merges when the immune system is compromised. The pathogenic bacterium employs an elaborate antioxidant defence machinery composed of the mycothiol- and thioredoxin system in addition to a superoxide dismutase, a catalase, and peroxiredoxins (Prxs). Among the family of Peroxiredoxins, Mtb expresses a 1-cysteine peroxiredoxin, known as alkylhydroperoxide reductase E (MtAhpE), and defined as a potential tuberculosis drug target. The reduced MtAhpE (MtAhpE-SH) scavenges peroxides to become converted to MtAhpE-SOH. To provide continuous availability of MtAhpE-SH, MtAhpE-SOH has to become reduced. Here, we used NMR spectroscopy to delineate the reduced (MtAhpE-SH), sulphenic (MtAhpE-SOH) and sulphinic (MtAhpE-SO2H) states of MtAhpE through cysteinyl-labelling, and provide for the first time evidence of a mycothiol-dependent mechanism of MtAhpE reduction. This is confirmed by crystallographic studies, wherein MtAhpE was crystallized in the presence of mycothiol and the structure was solved at 2.43Å resolution. Combined with NMR-studies, the crystallographic structures reveal conformational changes of important residues during the catalytic cycle of MtAhpE. In addition, alterations of the overall protein in solution due to redox modulation are observed by small angle X-ray scattering (SAXS) studies. Finally, by employing SAXS and dynamic light scattering, insight is provided into the most probable physiological oligomeric state of MtAhpE necessary for activity, being also discussed in the context of concerted substrate binding inside the dimeric MtAhpE.
URI: https://hdl.handle.net/10356/84711
http://hdl.handle.net/10220/41922
ISSN: 0891-5849
DOI: 10.1016/j.freeradbiomed.2016.07.007
Rights: © 2016 Elsevier. This is the author created version of a work that has been peer reviewed and accepted for publication by Free Radical Biology and Medicine, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.freeradbiomed.2016.07.007].
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:SBS Journal Articles

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