Gunka, Katrin

[["dc.bibliographiccitation.firstpage","1036"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Journal of Bacteriology"],["dc.bibliographiccitation.lastpage","1044"],["dc.bibliographiccitation.volume","194"],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Tholen, Stefan"],["dc.contributor.author","Gerwig, Jan"],["dc.contributor.author","Herzberg, Christina"],["dc.contributor.author","Stuelke, Joerg"],["dc.contributor.author","Commichau, Fabian M."],["dc.date.accessioned","2018-11-07T09:13:08Z"],["dc.date.available","2018-11-07T09:13:08Z"],["dc.date.issued","2012"],["dc.description.abstract","Common laboratory strains of Bacillus subtilis encode two glutamate dehydrogenases: the enzymatically active protein RocG and the cryptic enzyme GudB that is inactive due to a duplication of three amino acids in its active center. The inactivation of the rocG gene results in poor growth of the bacteria on complex media due to the accumulation of toxic intermediates. Therefore, rocG mutants readily acquire suppressor mutations that decryptify the gudB gene. This decryptification occurs by a precise deletion of one part of the 9-bp direct repeat that causes the amino acid duplication. This mutation occurs at the extremely high frequency of 10(-4). Mutations affecting the integrity of the direct repeat result in a strong reduction of the mutation frequency; however, the actual sequence of the repeat is not essential. The mutation frequency of gudB was not affected by the position of the gene on the chromosome. When the direct repeat was placed in the completely different context of an artificial promoter, the precise deletion of one part of the repeat was also observed, but the mutation frequency was reduced by 3 orders of magnitude. Thus, transcription of the gudB gene seems to be essential for the high frequency of the appearance of the gudB1 mutation. This idea is supported by the finding that the transcription-repair coupling factor Mfd is required for the decryptification of gudB. The Mfd-mediated coupling of transcription to mutagenesis might be a built-in precaution that facilitates the accumulation of mutations preferentially in transcribed genes."],["dc.identifier.doi","10.1128/JB.06470-11"],["dc.identifier.isi","000300530800015"],["dc.identifier.pmid","22178973"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/27106"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Microbiology"],["dc.relation.issn","0021-9193"],["dc.title","A High-Frequency Mutation in Bacillus subtilis: Requirements for the Decryptification of the gudB Glutamate Dehydrogenase Gene"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2004"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Journal of Biological Chemistry"],["dc.bibliographiccitation.lastpage","2017"],["dc.bibliographiccitation.volume","288"],["dc.contributor.author","Mehne, Felix M. P."],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Eilers, Hinnerk"],["dc.contributor.author","Herzberg, Christina"],["dc.contributor.author","Kaever, Volkhard"],["dc.contributor.author","Stuelke, Joerg"],["dc.date.accessioned","2018-11-07T09:29:07Z"],["dc.date.available","2018-11-07T09:29:07Z"],["dc.date.issued","2013"],["dc.description.abstract","The genome of the Gram-positive soil bacterium Bacillus subtilis encodes three potential diadenylate cyclases that may synthesize the signaling nucleotide cyclic di-AMP (c-di-AMP). These enzymes are expressed under different conditions in different cell compartments, and they localize to distinct positions in the cell. Here we demonstrate the diadenylate cyclase activity of the so far uncharacterized enzymes CdaA (previously known as YbbP) and CdaS (YojJ). Our work confirms that c-di-AMP is essential for the growth of B. subtilis and shows that an excess of the molecule is also harmful for the bacteria. Several lines of evidence suggest that the diadenylate cyclase CdaA is part of the conserved essential cda-glm module involved in cell wall metabolism. In contrast, the CdaS enzyme seems to provide c-di-AMP for spores. Accumulation of large amounts of c-di-AMP impairs the growth of B. subtilis and results in the formation of aberrant curly cells. This phenotype can be partially suppressed by elevated concentrations of magnesium. These observations suggest that c-di-AMP interferes with the peptidoglycan synthesis machinery. The activity of the diadenylate cyclases is controlled by distinct molecular mechanisms. CdaA is stimulated by a regulatory interaction with the CdaR (YbbR) protein. In contrast, the activity of CdaS seems to be intrinsically restricted, and a single amino acid substitution is sufficient to drastically increase the activity of the enzyme. Taken together, our results support the idea of an important role for c-di-AMP in B. subtilis and suggest that the levels of the nucleotide have to be tightly controlled."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft"],["dc.identifier.doi","10.1074/jbc.M112.395491"],["dc.identifier.isi","000313751400052"],["dc.identifier.pmid","23192352"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30943"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Biochemistry Molecular Biology Inc"],["dc.relation.issn","0021-9258"],["dc.title","Cyclic Di-AMP Homeostasis in Bacillus subtilis BOTH LACK AND HIGH LEVEL ACCUMULATION OF THE NUCLEOTIDE ARE DETRIMENTAL FOR CELL GROWTH"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","815"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Journal of Molecular Biology"],["dc.bibliographiccitation.lastpage","827"],["dc.bibliographiccitation.volume","400"],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Newman, Joseph A."],["dc.contributor.author","Commichau, Fabian M."],["dc.contributor.author","Herzberg, Christina"],["dc.contributor.author","Rodrigues, Cecilia"],["dc.contributor.author","Hewitt, Lorraine"],["dc.contributor.author","Lewis, Richard J."],["dc.contributor.author","Stuelke, Joerg"],["dc.date.accessioned","2018-11-07T08:41:18Z"],["dc.date.available","2018-11-07T08:41:18Z"],["dc.date.issued","2010"],["dc.description.abstract","Any signal transduction requires communication between a sensory component and an effector. Some enzymes engage in signal perception and transduction, as well as in catalysis, and these proteins are known as \"trigger\" enzymes. In this report, we detail the trigger properties of RocG, the glutamate dehydrogenase of Bacillus subtilis. RocG not only deaminates the key metabolite glutamate to form alpha-ketoglutarate but also interacts directly with GltC, a LysR-type transcription factor that regulates glutamate biosynthesis from alpha-ketoglutarate, thus linking the two metabolic pathways. We have isolated mutants of RocG that separate the two functions. Several mutations resulted in permanent inactivation of GltC as long as a source of glutamate was present. These RocG proteins have lost their ability to catabolize glutamate due to a strongly reduced affinity for glutamate. The second class of mutants is exemplified by the replacement of aspartate residue 122 by asparagine. This mutant protein has retained enzymatic activity but has lost the ability to control the activity of GltC. Crystal structures of glutamate dehydrogenases that permit a molecular explanation of the properties of the various mutants are presented. Specifically, we may propose that D122N replacement affects the surface of RocG. Our data provide evidence for a correlation between the enzymatic activity of RocG and its ability to inactivate GltC, and thus give insights into the mechanism that couples the enzymatic activity of a trigger enzyme to its regulatory function. (C) 2010 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.jmb.2010.05.055"],["dc.identifier.isi","000280652300014"],["dc.identifier.pmid","20630473"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/19436"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Academic Press Ltd- Elsevier Science Ltd"],["dc.relation.issn","0022-2836"],["dc.title","Functional Dissection of a Trigger Enzyme: Mutations of the Bacillus subtilis Glutamate Dehydrogenase RocG That Affect Differentially Its Catalytic Activity and Regulatory Properties"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5997"],["dc.bibliographiccitation.issue","21"],["dc.bibliographiccitation.journal","Journal of Bacteriology"],["dc.bibliographiccitation.lastpage","6007"],["dc.bibliographiccitation.volume","193"],["dc.contributor.author","Diethmaier, Christine"],["dc.contributor.author","Pietack, Nico"],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Wrede, Christoph"],["dc.contributor.author","Lehnik-Habrink, Martin"],["dc.contributor.author","Herzberg, Christina"],["dc.contributor.author","Huebner, Sebastian"],["dc.contributor.author","Stuelke, Joerg"],["dc.date.accessioned","2018-11-07T08:50:29Z"],["dc.date.available","2018-11-07T08:50:29Z"],["dc.date.issued","2011"],["dc.description.abstract","Cells of Bacillus subtilis can either be motile or sessile, depending on the expression of mutually exclusive sets of genes that are required for flagellum or biofilm formation, respectively. Both activities are coordinated by the master regulator SinR. We have analyzed the role of the previously uncharacterized ymdB gene for bistable gene expression in B. subtilis. We observed a strong overexpression of the hag gene encoding flagellin and of other genes of the sigma(D)-dependent motility regulon in the ymdB mutant, whereas the two major operons for biofilm formation, tapA-sipW-tasA and epsA-O, were not expressed. As a result, the ymdB mutant is unable to form biofilms. An analysis of the individual cells of a population revealed that the ymdB mutant no longer exhibited bistable behavior; instead, all cells are short and motile. The inability of the ymdB mutant to form biofilms is suppressed by the deletion of the sinR gene encoding the master regulator of biofilm formation, indicating that SinR-dependent repression of biofilm genes cannot be relieved in a ymdB mutant. Our studies demonstrate that lack of expression of SlrR, an antagonist of SinR, is responsible for the observed phenotypes. Overexpression of SlrR suppresses the effects of a ymdB mutation."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft [SFB860]; Fonds der Chemischen Industrie"],["dc.identifier.doi","10.1128/JB.05360-11"],["dc.identifier.isi","000296153400012"],["dc.identifier.pmid","21856853"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21703"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Microbiology"],["dc.relation.issn","0021-9193"],["dc.title","A Novel Factor Controlling Bistability in Bacillus subtilis: the YmdB Protein Affects Flagellin Expression and Biofilm Formation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","eaal3011"],["dc.bibliographiccitation.issue","475"],["dc.bibliographiccitation.journal","Science Signaling"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Gundlach, Jan"],["dc.contributor.author","Herzberg, Christina"],["dc.contributor.author","Kaever, Volkhard"],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Hoffmann, Tamara"],["dc.contributor.author","Weiss, Martin"],["dc.contributor.author","Gibhardt, Johannes"],["dc.contributor.author","Thuermer, Andrea"],["dc.contributor.author","Hertel, Dietrich"],["dc.contributor.author","Daniel, Rolf"],["dc.contributor.author","Bremer, Erhard"],["dc.contributor.author","Commichau, Fabian M."],["dc.contributor.author","Stulke, Joerg"],["dc.date.accessioned","2018-11-07T10:24:56Z"],["dc.date.available","2018-11-07T10:24:56Z"],["dc.date.issued","2017"],["dc.description.abstract","The second messenger cyclic di-adenosine monophosphate (c-di-AMP) is essential in the Gram-positive model organism Bacillus subtilis and in related pathogenic bacteria. It controls the activity of the conserved ydaO riboswitch and of several proteins involved in potassium (K+) uptake. We found that the YdaO protein was conserved among several different bacteria and provide evidence that YdaO functions as a K+ transporter. Thus, we renamed the gene and protein KimA (K+ importer A). Reporter activity assays indicated that expression beyond the c-di-AMP-responsive riboswitch of the kimA upstream regulatory region occurred only in bacteria grown in medium containing low K+ concentrations. Furthermore, mass spectrometry analysis indicated that c-di-AMP accumulated in bacteria grown in the presence of high K+ concentrations but not in low concentrations. A bacterial strain lacking all genes encoding c-di-AMP-synthesizing enzymes was viable when grown in medium containing low K+ concentrations, but not at higher K+ concentrations unless it acquired suppressor mutations in the gene encoding the cation exporter NhaK. Thus, our results indicated that the control of potassium homeostasis is an essential function of c-di-AMP."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft [SPP1879]"],["dc.identifier.doi","10.1126/scisignal.aal3011"],["dc.identifier.isi","000400128400003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/42751"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","PUB_WoS_Import"],["dc.publisher","Amer Assoc Advancement Science"],["dc.relation.issn","1937-9145"],["dc.relation.issn","1945-0877"],["dc.title","Control of potassium homeostasis is an essential function of the second messenger cyclic di-AMP in Bacillus subtilis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]