Expression, purification, crystallization and preliminary X-ray analysis of the DNA-binding domain of<i>Rhodobacter capsulatus</i>MopB

Müller, Alexandra; Schlicker, Christine; Fehringer, Maria; Masepohl, Bernd; Hofmann, Eckhard

doi:10.1107/s1744309110054710

Cited by 2 publications

(2 citation statements)

References 23 publications

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“…S1). Similar molybdate‐independent promoter‐binding was previously observed for a truncated variant of the Rhodobacter capsulatus ModE homolog, MopB, devoid of its molybdate‐binding domain (Müller et al ., ).…”

Section: Resultsmentioning

confidence: 97%

Molybdate uptake by Agrobacterium tumefaciens correlates with the cellular molybdenum cofactor status

Hoffmann

Ali

Sonnenschein

et al. 2016

Molecular Microbiology

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Many enzymes require the molybdenum cofactor, Moco. Under Mo-limiting conditions, the high-affinity ABC transporter ModABC permits molybdate uptake and Moco biosynthesis in bacteria. Under Mo-replete conditions, Escherichia coli represses modABC transcription by the one-component regulator, ModE, consisting of a DNA-binding and a molybdate-sensing domain. Instead of a full-length ModE protein, many bacteria have a shorter ModE protein, ModE(S) , consisting of a DNA-binding domain only. Here, we asked how such proteins sense the intracellular molybdenum status. We show that the Agrobacterium tumefaciens ModE(S) protein Atu2564 is essential for modABC repression. ModE(S) binds two Mo-boxes in the modA promoter as shown by electrophoretic mobility shift assays. Northern analysis revealed cotranscription of modE(S) with the upstream gene, atu2565, which was dispensable for ModE(S) activity. To identify genes controlling ModE(S) function, we performed transposon mutagenesis. Tn5 insertions resulting in derepressed modA transcription mapped to the atu2565-modE(S) operon and several Moco biosynthesis genes. We conclude that A. tumefaciens ModE(S) activity responds to Moco availability rather than to molybdate concentration directly, as is the case for E. coli ModE. Similar results in Sinorhizobium meliloti suggest that Moco dependence is a common feature of ModE(S) regulators.

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Section: Resultsmentioning

confidence: 97%

Molybdate uptake by Agrobacterium tumefaciens correlates with the cellular molybdenum cofactor status

Hoffmann

Ali

Sonnenschein

et al. 2016

Molecular Microbiology

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“…Like E. coli ModE, MopA and MopB are one‐component molybdate‐sensing regulatory proteins. Molybdate binding enhances affinity to their target promoters (Gourley et al , ; Schüttelkopf et al , ; Wiethaus et al , ), and the separated HTH domain of MopB (lacking the molybdate‐binding domain) still binds the anfA promoter (Müller et al , ). As expected, molybdate does no longer increase binding.…”

Section: Mo‐responsive Gene Regulation By Two Mode Homologs In Rhodobmentioning

confidence: 99%

Coordinated regulation of nitrogen fixation and molybdate transport by molybdenum

Demtröder

Narberhaus

Masepohl

2018

Molecular Microbiology

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Summary Biological nitrogen fixation, the reduction of chemically inert dinitrogen to bioavailable ammonia, is a central process in the global nitrogen cycle highly relevant for life on earth. N2 reduction to NH3 is catalyzed by nitrogenases exclusively synthesized by diazotrophic prokaryotes. All diazotrophs have a molybdenum nitrogenase containing the unique iron‐molybdenum cofactor FeMoco. In addition, some diazotrophs encode one or two alternative Mo‐free nitrogenases that are less efficient at reducing N2 than Mo‐nitrogenase. To permit biogenesis of Mo‐nitrogenase and other molybdoenzymes when Mo is scarce, bacteria synthesize the high‐affinity molybdate transporter ModABC. Generally, Mo supports expression of Mo‐nitrogenase genes, while it represses production of Mo‐free nitrogenases and ModABC. Since all three nitrogenases and ModABC can reach very high levels at suitable Mo concentrations, tight Mo‐mediated control saves considerable resources and energy. This review outlines the similarities and differences in Mo‐responsive regulation of nitrogen fixation and molybdate transport in diverse diazotrophs.

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Expression, purification, crystallization and preliminary X-ray analysis of the DNA-binding domain ofRhodobacter capsulatusMopB

Cited by 2 publications

References 23 publications

Molybdate uptake by Agrobacterium tumefaciens correlates with the cellular molybdenum cofactor status

Molybdate uptake by Agrobacterium tumefaciens correlates with the cellular molybdenum cofactor status

Coordinated regulation of nitrogen fixation and molybdate transport by molybdenum

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