Amino Acid Residues of RegA Important for Interactions with the CbbR-DNA Complex of Rhodobacter sphaeroides

Dangel, Andrew W.; Luther, Amanda; Tabita, F. Robert

doi:10.1128/jb.01842-14

Cited by 11 publications

(18 citation statements)

References 52 publications

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“…Cross-linking experiments, using a bifunctional binding compound, indicated that RegA and CbbR form a stoichiometric complex, results that were buttressed by gel mobility shift assays that also showed specific interactions between RegA and CbbR-bound DNA (58). In addition, extensive mutational analyses provided evidence that CbbR and RegA interact with each other through their DBDs (59). A model for this rather complex regulatory scenario, which is based on several lines of evidence and provides a likely explanation for how CbbR and RegA interact to regulate cbb gene expression and, subsequently, CO 2 fixation in R. sphaeroides, is presented in Fig.…”

Section: Interactions With Cbbr: the Case Of Dueling Transcription Famentioning

confidence: 93%

“…However, in the case of some phototrophic bacteria, regulation of cbb expression is much more complex, imposing additional layers of regulation on the energetically costly process of CO 2 assimilation. There are two well-studied systems that illustrate this regulatory complexity: interaction of CbbR with additional (and different) transcription regulators in R. sphaeroides and R. palustris (58)(59)(60)(61).…”

Section: Interactions With Cbbr: the Case Of Dueling Transcription Famentioning

confidence: 99%

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CbbR, the Master Regulator for Microbial Carbon Dioxide Fixation

Dangel

Tabita

2015

J Bacteriol

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Biological carbon dioxide fixation is an essential and crucial process catalyzed by both prokaryotic and eukaryotic organisms to allow ubiquitous atmospheric CO 2 to be reduced to usable forms of organic carbon. This process, especially the CalvinBassham-Benson (CBB) pathway of CO 2 fixation, provides the bulk of organic carbon found on earth. The enzyme ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (RubisCO) performs the key and rate-limiting step whereby CO 2 is reduced and incorporated into a precursor organic metabolite. This is a highly regulated process in diverse organisms, with the expression of genes that comprise the CBB pathway (the cbb genes), including RubisCO, specifically controlled by the master transcriptional regulator protein CbbR. Many organisms have two or more cbb operons that either are regulated by a single CbbR or employ a specific CbbR for each cbb operon. CbbR family members are versatile and accommodate and bind many different effector metabolites that influence CbbR's ability to control cbb transcription. Moreover, two members of the CbbR family are further posttranslationally modified via interactions with other transcriptional regulator proteins from two-component regulatory systems, thus augmenting CbbR-dependent control and optimizing expression of specific cbb operons. In addition to interactions with small effector metabolites and other regulator proteins, CbbR proteins may be selected that are constitutively active and, in some instances, elevate the level of cbb expression relative to wild-type CbbR. Optimizing CbbR-dependent control is an important consideration for potentially using microbes to convert CO 2 to useful bioproducts.

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Section: Interactions With Cbbr: the Case Of Dueling Transcription Famentioning

confidence: 93%

Section: Interactions With Cbbr: the Case Of Dueling Transcription Famentioning

confidence: 99%

CbbR, the Master Regulator for Microbial Carbon Dioxide Fixation

Dangel

Tabita

2015

J Bacteriol

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“…Truncated NAC also has all the known properties of full-length NAC (Muse & Bender, 1999). Although it is a different member of the LTTR family, the NAC DBD/linker helix truncation has activity, but a similar truncation in the CbbR of Rhodobacter sphaeroides does not have CbbR * activity and cannot support autotrophic growth in vivo (Dangel et al, 2014). This is quite distinct from the situation in the related cbb regulon system of Ralstonia eutropha, although in vitro studies indicate that the DBD/ linker helix CbbR truncation of Rhodobacter sphaeroides does bind its cbb I promoter (Dangel et al, 2014).…”

Section: A Truncated Cbbr Protein Containing Only the Dbd And Linker mentioning

confidence: 64%

“…Modified CbbR * conformations could also lead to stronger or more stable promoter DNA binding and subsequently to more productive interactions with RNA polymerase. The constitutive amino acid substitutions in the linker helix may also contribute to improved DNA stability, as it has been demonstrated through deletion studies that the linker helix of the CbbR from Rhodobacter sphaeroides is necessary for DNA binding (Dangel et al, 2014). Many amino acid substitutions that cause enhanced CbbR * activity are near the effector pocket.…”

Section: Amino Acid Substitutions In the Ralstonia Eutropha Cbbr Protmentioning

confidence: 99%

“…Although it is a different member of the LTTR family, the NAC DBD/linker helix truncation has activity, but a similar truncation in the CbbR of Rhodobacter sphaeroides does not have CbbR * activity and cannot support autotrophic growth in vivo (Dangel et al, 2014). This is quite distinct from the situation in the related cbb regulon system of Ralstonia eutropha, although in vitro studies indicate that the DBD/ linker helix CbbR truncation of Rhodobacter sphaeroides does bind its cbb I promoter (Dangel et al, 2014). Possibly, the truncated CbbR of Rhodobacter sphaeroides has no in vivo activity because cbb expression in Rhodobacter sphaeroides is complicated by the fact that CbbR must also bind the response regulator RegA (Dangel & Tabita, 2009).…”

Section: A Truncated Cbbr Protein Containing Only the Dbd And Linker mentioning

confidence: 99%

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Amino acid substitutions in the transcriptional regulator CbbR lead to constitutively active CbbR proteins that elevate expression of the cbb CO2 fixation operons in Ralstonia eutropha (Cupriavidus necator) and identify regions of CbbR necessary for gene activation

Dangel

Tabita

2015

Microbiology

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CbbR is a LysR-type transcriptional regulator that activates expression of the operons containing (cbb) genes that encode the CO 2 fixation pathway enzymes in Ralstonia eutropha (Cupriavidus necator) under autotrophic growth conditions. The cbb operons are stringently downregulated during chemoheterotrophic growth on organic acids such as malate. CbbR constitutive proteins (CbbR*s), typically with single amino acid substitutions, were selected and isolated that activate expression of the cbb operons under chemoheterotrophic growth conditions. A large set of CbbR * s from all major domains of the CbbR molecule were identified, except for the DNA-binding domain. The level of gene expression conferred for many of these CbbR * s under autotrophic growth was greater than that conferred by wild-type CbbR. Several of these CbbR * s increase transcription two-to threefold more than wild-type CbbR. One particular CbbR*, a truncated protein, was useful in identifying the regions of CbbR that are necessary for transcriptional activation and, by logical extension, necessary for interaction with RNA polymerase. The reductive assimilation of carbon via CO 2 fixation is an important step in the cost-effective production of useful biological compounds. Enhancing CO 2 fixation in Ralstonia eutropha through greater transcriptional activation of the cbb operons could prove advantageous, and the use of CbbR * s is one way to enhance product formation.

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Isolation of a Rhodobacter sphaeroides mutant with enhanced hydrogen production capacity from transposon mutagenesis by NH4+ nitrogen resource

Wang

et al. 2018

International Journal of Hydrogen Energy

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Amino Acid Residues of RegA Important for Interactions with the CbbR-DNA Complex of Rhodobacter sphaeroides

Cited by 11 publications

References 52 publications

CbbR, the Master Regulator for Microbial Carbon Dioxide Fixation

CbbR, the Master Regulator for Microbial Carbon Dioxide Fixation

Amino acid substitutions in the transcriptional regulator CbbR lead to constitutively active CbbR proteins that elevate expression of the cbb CO2 fixation operons in Ralstonia eutropha (Cupriavidus necator) and identify regions of CbbR necessary for gene activation

Isolation of a Rhodobacter sphaeroides mutant with enhanced hydrogen production capacity from transposon mutagenesis by NH4+ nitrogen resource

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