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Type II flavohemoglobin of Mycobacterium smegmatis oxidizes d-lactate and mediate electron transfer.

DIR@IMTECH: CSIR-Institute of Microbial Technology

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Title Type II flavohemoglobin of Mycobacterium smegmatis oxidizes d-lactate and mediate electron transfer.
 
Creator Thakur, Naveen
Kumar, Ashwani
Dikshit, Kanak L
 
Subject QR Microbiology
 
Description Two distantly related flavohemoglobins (FHbs), MsFHbI and MsFHbII, having crucial differences in their heme and reductase domains, co-exist in Mycobacterium smegmatis. Function of MsFHbI is associated with nitric-oxide detoxification but physiological relevance of MsFHbII remains unknown. This study unravels some unique spectral and functional characteristics of MsFHbII. Unlike conventional type I FHbs, MsFHbII lacks nitric-oxide dioxygenase and NADH oxidase activities but utilizes d-lactate as an electron donor to mediate electron transfer. MsFHbII carries a d-lactate dehydrogenase type FAD binding motif in its reductase domain and oxidizes d-lactate in a FAD dependent manner to reduce the heme iron, suggesting that the globin is acting as an electron acceptor. Importantly, expression of MsFHbII in Escherichia coli imparted protection under oxidative stress, suggesting its important role in stress management of its host. Since M. smegmatis lacks the gene encoding for d-lactate dehydrogenase and d-lactate is produced during aerobic metabolism and also as a by-product of lipid peroxidation, the ability of MsFHbII to metabolize d-lactate may provide it a unique ability to balance the oxidative stress generated due to accumulation of d-lactate in the cell and at the same time sequester electrons and pass it to the respiratory apparatus.
 
Publisher Elsevier Science
 
Date 2018-06-07
 
Type Article
PeerReviewed
 
Relation https://linkinghub.elsevier.com/retrieve/pii/S0141-8130(17)34897-3
http://crdd.osdd.net/open/2183/
 
Identifier Thakur, Naveen and Kumar, Ashwani and Dikshit, Kanak L (2018) Type II flavohemoglobin of Mycobacterium smegmatis oxidizes d-lactate and mediate electron transfer. International journal of biological macromolecules, 112. pp. 868-875. ISSN 1879-0003