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Unique gene organization of thioredoxin and thioredoxin reductase in Mycobacterium leprae
Author(s) -
Wieles Brigitte,
Soolingen Dick,
Holmgren Arne,
Offringa Rienk,
Ottenhoff Tom,
Thole Jelle
Publication year - 1995
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1995.tb02318.x
Subject(s) - thioredoxin , biology , thioredoxin reductase , mycobacterium leprae , gene , reductase , mycobacterium , genetics , bacteria , biochemistry , microbiology and biotechnology , enzyme , leprosy , immunology
Summary The thioredoxin system comprising thioredoxin (Trx), thioredoxin reductase (TR) and NADPH operates via redox‐active disulphides and provides electrons for a wide variety of different metabolic processes in prokaryotic and eukaryotic cells. Thioredoxin is also a general protein disulphide reductase involved in redox regulation. In bacteria, the Trx and TR proteins previously identified were encoded by separate genes ( trxA and trxB ). In this study, we report a novel genomic organization of TR and Trx in mycobacteria and show that at least three modes of organization of TR and Trx genes can exist within a single bacterial genus: (i) in the majority of mycobacterial strains the genes coding for TR and Trx are located on separate sites of the genome; (ii) interestingly, in all pathogenic Mycobacterium tuberculosis complex mycobacteria both genes are found on the same locus, overlapping in one nucleotide; (iii) in the pathogen Mycobacterium leprae , TR and Trx are encoded by a single gene. Sequence analysis of the M. leprae gene demonstrated that the N‐terminal part of the protein corresponds to TR and the C‐terminal part to Trx. A corresponding single protein product of approximately 49 kDa was detected in cell extracts of M. leprae. These findings demonstrate the very unusual phenomenon of a single gene coding for both the substrate (thioredoxin) and the enzyme (thioredoxin reductase), which seems to be unique to M. leprae.