Characterization of the ModABC Molybdate Transport System of in Nicotine Degradation.

Author(s) Xia, Z.; Lei, L.; Zhang, H.Y.; Wei, H.L.
Journal Front Microbiol
Date Published 2018
Abstract

J5 is an efficient nicotine-degrading bacterial strain that catabolizes nicotine through the pyrrolidine pathway. In our previous study, we used Tn5 transposon mutagenesis to investigate nicotine metabolism-associated genes, and 18 nicotine degradation-deficient mutants were isolated from 16,324 Tn-transformants. Three of the mutants were Tn5 inserts into the gene cluster that encoded an ABC-type, high-affinity, molybdate transporter. In-frame deletion of the genes abolished the nicotine-degrading ability of strain J5, and complementation with either from or restored the degrading activity of the mutant to wild-type level. Nicotine degradation of J5 was inhibited markedly by addition of tungstate, a specific antagonist of molybdate. Molybdate at a non-physiologically high concentration (100 μM) fully restored nicotine-degrading activity and recovered growth of the mutant in a nicotine minimal medium. Transcriptional analysis revealed that the expression of was up-regulated at low molybdate concentrations and down-regulated at high moybdate concentrations, which indicated that at least one other system was able to transport molybdate, but with lower affinity. These results suggested that the molybdate transport system was essential to nicotine metabolism in J5.

DOI 10.3389/fmicb.2018.03030
ISSN 1664-302X
Citation Xia Z, Lei L, Zhang H-, Wei H-. Characterization of the ModABC Molybdate Transport System of in Nicotine Degradation. Front Microbiol. 2018;9:3030.

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