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amtR Nitrogen

Madhumati Sevvana, Kristin Hasselt, Florian C Grau, Andreas Burkovski, Yves A Muller
AmtR belongs to the TetR family of transcription regulators and is a global nitrogen regulator that is induced under nitrogen-starvation conditions in Corynebacterium glutamicum. AmtR regulates the expression of transporters and enzymes for the assimilation of ammonium and alternative nitrogen sources, for example urea, amino acids etc. The recognition of operator DNA by homodimeric AmtR is not regulated by small-molecule effectors as in other TetR-family members but by a trimeric adenylylated PII -type signal transduction protein named GlnK...
March 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
Michael Petridis, Chelsea Vickers, Jennifer Robson, Joanna L McKenzie, Magdalena Bereza, Abigail Sharrock, Htin Lin Aung, Vickery L Arcus, Gregory M Cook
Soil-dwelling bacteria of the phylum actinomycetes generally harbor either GlnR or AmtR as a global regulator of nitrogen metabolism. Mycobacterium smegmatis harbors both of these canonical regulators; GlnR regulates the expression of key genes involved in nitrogen metabolism, while the function and signal transduction pathway of AmtR in M. smegmatis remains largely unknown. Here, we report the structure and function of the M. smegmatis AmtR and describe the role of AmtR in the regulation of nitrogen metabolism in response to nitrogen availability...
October 23, 2016: Journal of Molecular Biology
Carles Palanca, Vicente Rubio
UNLABELLED: Corynebacterium glutamicum is a bacterium used for industrial amino acid production, and understanding its metabolic pathway regulation is of high biotechnological interest. Here, we report crystal structures of AmtR, the global nitrogen regulator of C. glutamicum, in apo (2.25-Å and 2.65-Å resolution) and DNA-bound (3-Å resolution) forms. These structures reveal an all-α homodimeric TetR family regulator composed of a helix-turn-helix-hosting N-terminal DNA-binding domain and a C-terminal dimerization domain...
March 2016: FEBS Journal
Nadja Jeßberger, Yinhua Lu, Johannes Amon, Fritz Titgemeyer, Sophia Sonnewald, Stephen Reid, Andreas Burkovski
BACKGROUND: As other bacteria, Mycobacterium smegmatis needs adaption mechanisms to cope with changing nitrogen sources and to survive situations of nitrogen starvation. In the study presented here, transcriptome analyses were used to characterize the response of the bacterium to nitrogen starvation and to elucidate the role of specific transcriptional regulators. RESULTS: In response to nitrogen deprivation, a general starvation response is induced in M. smegmatis...
November 22, 2013: BMC Research Notes
Yunliang Chen, Hong Zhu, Guosong Zheng, Weihong Jiang, Yinhua Lu
In actinomycetes, two main regulators, the OmpR-like GlnR and the TetR-type AmtR, have been identified as the central regulators for nitrogen metabolism. GlnR-mediated regulation was previously identified in different actinomycetes except for members of the genus Corynebacterium, in which AmtR plays a predominant role in nitrogen metabolism. Interestingly, some actinomycetes (e.g. Streptomyces avermitilis) harbour both glnR- and amtR-homologous genes in the chromosome. Thus, it will be interesting to determine how these two different types of regulators function together in nitrogen regulation of these strains...
December 2013: Microbiology
Jens P Krause, Tino Polen, Jung-Won Youn, Denise Emer, Bernhard J Eikmanns, Volker F Wendisch
Corynebacterium glutamicum is a Gram-positive nonpathogenic bacterium that is used for the biotechnological production of amino acids. Here, we investigated the transcriptional control of the malE gene encoding malic enzyme (MalE) in C. glutamicum ATCC 13032, which is known to involve the nitrogen regulator AmtR. Gel shift experiments using purified regulators RamA and RamB revealed binding of these regulators to the malE promoter. In DNA-affinity purification experiments a hitherto uncharacterized transcriptional regulator belonging to the MarR family was found to bind to malE promoter DNA and was designated as MalR...
June 15, 2012: Journal of Biotechnology
N Hao, M Yan, H Zhou, H M Liu, P Cai, P K Ouyang
AmtR, the master regulator of nitrogen control in Corynebacterium glutamicum, plays important roles in nitrogen metabolism. To investigate the influence of AmtR on amino acids production in C. glutamicum ATCC 13032, the amtR deletion strain C. glutamicum Q1 was constructed and cultured in modified CGXII minimal medium for 60 h. The ammonium consumption rates as well as amino acids production of both strains cultured in modified CGXII minimal medium were determined. The amtR deletion in C. glutamicum caused an obvious growth defect in the exponential growth phase, but both strains had the same biomass in the stationary phases...
November 2010: Prikladnaia Biokhimiia i Mikrobiologiia
Kristin Hasselt, Simone Rankl, Stefanie Worsch, Andreas Burkovski
In corynebacteria, nitrogen regulation is controlled by the TetR family protein AmtR, which was extensively studied in the last years. In frame of these studies a number of AmtR binding sites were identified and characterized and it became obvious that for distinct genes the number and sequences of these sites varied significantly. In this study, the influence of numbers and alterations of AmtR binding sites were addressed by in vivo and in vitro studies. It can be concluded that in general a single highly conserved AmtR site is sufficient for stringent regulation and that non-conserved binding sites have a very limited influence, despite the fact that binding of AmtR was shown for several of these sites, e...
July 10, 2011: Journal of Biotechnology
Nadine Rehm, Tobias Georgi, Eva Hiery, Ursula Degner, Alfred Schmiedl, Andreas Burkovski, Michael Bott
Corynebacterium glutamicum, a Gram-positive soil bacterium employed in the industrial production of various amino acids, is able to use a number of different nitrogen sources, such as ammonium, urea or creatinine. This study shows that l-glutamine serves as an excellent nitrogen source for C. glutamicum and allows similar growth rates in glucose minimal medium to those in ammonium. A transcriptome comparison revealed that the nitrogen starvation response was elicited when glutamine served as the sole nitrogen source, meaning that the target genes of the global nitrogen regulator AmtR were derepressed...
October 2010: Microbiology
Kristin Hasselt, Madhumati Sevvana, Andreas Burkovski, Yves A Muller
AmtR, a member of the TetR family of transcription regulators, is a global regulator of nitrogen control in Corynebacterium glutamicum. Unlike other TetR-family members, which are regulated by small-molecule effectors, AmtR is regulated by a protein called GlnK. It has been shown that a GlnK trimer has to become adenylylated prior to formation of a complex with AmtR. The physiological function of AmtR has been very well studied, but structural characterization of the mechanistic aspects of AmtR-regulated transcription has yet to be accomplished...
November 1, 2009: Acta Crystallographica. Section F, Structural Biology and Crystallization Communications
Daniela Muhl, Nadja Jessberger, Kristin Hasselt, Christophe Jardin, Heinrich Sticht, Andreas Burkovski
BACKGROUND: The TetR family member AmtR is the central regulator of nitrogen starvation response in Corynebacterium glutamicum. While the AmtR regulon was physiologically characterized in great detail up to now, mechanistic questions of AmtR binding were not addressed. This study presents a characterization of functionally important amino acids in the DNA binding domain of AmtR and of crucial nucleotides in the AmtR recognition motif. RESULTS: Site-directed mutagenesis, the characterization of corresponding mutant proteins by gel retardation assays and surface plasmon resonance and molecular modelling revealed several amino acids, which are directly involved in DNA binding, while others have more structural function...
July 23, 2009: BMC Molecular Biology
Eva Hänssler, Tim Müller, Katrin Palumbo, Mirek Patek, Melanie Brocker, Reinhard Krämer, Andreas Burkovski
Glutamate dehydrogenase is a central enzyme connecting nitrogen and carbon metabolism via its precursors ammonium and oxoglutarate and its product glutamate. In Corynebacterium glutamicum glutamate dehydrogenase is especially important, since it is a key enzyme for the biotechnological production of the flavour enhancer L-glutamate. In this study, the regulation of gdh transcription was investigated. While originally described as a constitutively expressed gene, we could show that gdh transcription is highly variable depending on environmental conditions...
June 15, 2009: Journal of Biotechnology
Sebastian Buchinger, Julia Strösser, Nadine Rehm, Eva Hänssler, Stephan Hans, Brigitte Bathe, Dietmar Schomburg, Reinhard Krämer, Andreas Burkovski
The effects of a deletion of the amtR gene, encoding the master regulator of nitrogen control in Corynebacterium glutamicum, were investigated by metabolome and transcriptome analyses. Compared to the wild type, different metabolite patterns were observed in respect to glycolysis, pentose phosphate pathway, citric acid cycle, and most amino acid pools. Not all of these alterations could be attributed to changes at the level of mRNA and must be caused by posttranscriptional regulatory processes. However, subsequently carried out transcriptome analyses, which were confirmed by gel retardation experiments, revealed two new targets of AmtR, the dapD gene, encoding succinylase involved in m-diaminopimelate synthesis, and the mez gene, coding for malic enzyme...
March 10, 2009: Journal of Biotechnology
Johannes Amon, Fritz Titgemeyer, Andreas Burkovski
Knowledge about nitrogen metabolism and control in the genus Mycobacterium is sparse, especially compared to the state of knowledge in related actinomycetes like Streptomyces coelicolor or the close relative Corynebacterium glutamicum. Therefore, we screened the published genome sequences of Mycobacterium smegmatis, Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium avium ssp. paratuberculosis and Mycobacterium leprae for genes encoding proteins for uptake of nitrogen sources, nitrogen assimilation and nitrogen control systems, resulting in a detailed comparative genomic analysis of nitrogen metabolism-related genes for all completely sequenced members of the genus...
2009: Journal of Molecular Microbiology and Biotechnology
Hideaki Takano, Akiko Shimizu, Rina Shibosawa, Rie Sasaki, Shino Iwagaki, Osamu Minagawa, Kazuki Yamanaka, Kiyoshi Miwa, Teruhiko Beppu, Kenji Ueda
We report that Corynebacterium glutamicum colonies exhibit a developmental transition in culture. When cultured on a routinely used complete medium (CM2B), this bacterium first formed a flat translucent colony. Subsequently, some parts of this colony expanded to form small spherical yellow colonies that finally developed into a single large yellow colony. The small flat colony consisted of long thick cells, which were occasionally V or Y shaped, while the large yellow colony consisted of short small rods. A similar colony development pattern was observed in Corynebacterium ammoniagenes and Corynebacterium callunae...
November 2008: Applied Microbiology and Biotechnology
Andreas Burkovski
In order to utilize different nitrogen sources and to survive in a situation of nitrogen limitation, microorganisms have developed sophisticated mechanisms to adapt their metabolism to a changing nitrogen supply. In this communication, the recent knowledge of nitrogen regulation in the amino acid producer Corynebacterium glutamicum is summarized. The core adaptations of C. glutamicum to nitrogen limitation on the level of transcription are controlled by the global regulator AmtR. Further components of the signal pathway are GlnK, a P(II)-type signal transduction protein, and GlnD...
February 2007: Journal of Microbiology and Biotechnology
Britta Walter, Eva Hänssler, Jörn Kalinowski, Andreas Burkovski
The published genome sequences of Corynebacterium diphtheriae, Corynebacterium efficiens, Corynebacterium glutamicum and Corynebacterium jeikeium were screened for genes encoding central components of nitrogen source uptake, nitrogen assimilation and nitrogen control systems. Interestingly, the soil-living species C. efficiens and C. glutamicum exhibit a broader spectrum of genes for nitrogen transport and metabolism than the pathogenic species C. diphtheriae and C. jeikeium. The latter are characterized by gene decay and loss of functions like urea metabolism and nitrogen-dependent transcription control...
2007: Journal of Molecular Microbiology and Biotechnology
Maike Silberbach, Andreas Burkovski
The regulation of nitrogen metabolism in the amino acid producer Corynebacterium glutamicum was subject of research for several decades. While previous studies focused on single enzymes or pathways, the publication of the C. glutamicum genome sequence gave a fresh impetus to research, since a global investigation of metabolism and regulation networks became possible based on these data. This communication summarizes the advances made by different studies, in which global analysis approaches were used to characterize the C...
October 20, 2006: Journal of Biotechnology
Gabriele Beckers, Julia Strösser, Ulrich Hildebrandt, Jörn Kalinowski, Mike Farwick, Reinhard Krämer, Andreas Burkovski
AmtR, the master regulator of nitrogen control in Corynebacterium glutamicum, represses transcription of a number of genes during nitrogen surplus. Repression is released by an interaction of AmtR with signal transduction protein GlnK. As shown by pull-down assays and gel retardation experiments, only adenylylated GlnK, which is present in the cells during nitrogen limitation, is able to bind to AmtR. The AmtR regulon was characterized in this study by a combination of bioinformatics, transcriptome and proteome analyses...
October 2005: Molecular Microbiology
Gabriele Beckers, Anne K Bendt, Reinhard Krämer, Andreas Burkovski
The molecular identification of the Corynebacterium glutamicum urea uptake system is described. This ABC-type transporter is encoded by the urtABCDE operon, which is transcribed in response to nitrogen limitation. Expression of the urt genes is regulated by the global nitrogen regulator AmtR, and an amtR deletion strain showed constitutive expression of the urtABCDE genes. The AmtR repressor protein also controls transcription of the urease-encoding ureABCEFGD genes in C. glutamicum. The ure gene cluster forms an operon which is mainly transcribed in response to nitrogen starvation...
November 2004: Journal of Bacteriology
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