scholarly journals Functional Characterization of the Stringent Response Regulatory Gene dksA of Vibrio cholerae and Its Role in Modulation of Virulence Phenotypes

2012 ◽  
Vol 194 (20) ◽  
pp. 5638-5648 ◽  
Author(s):  
R. R. Pal ◽  
S. Bag ◽  
S. Dasgupta ◽  
B. Das ◽  
R. K. Bhadra
Keyword(s):  
Vibrio Cholerae ◽  
Regulatory Gene ◽  
Functional Characterization ◽  
Stringent Response

Molecular and functional characterization of a second copy of the aflatoxin regulatory gene, aflR-2, from Aspergillus parasiticus

2002 ◽  
Vol 1576 (3) ◽  
pp. 316-323 ◽  
Author(s):  
Jeffrey W Cary ◽  
John M Dyer ◽  
Kenneth C Ehrlich ◽  
Maureen S Wright ◽  
Shun-Hsin Liang ◽  
...  
Keyword(s):  
Aspergillus Parasiticus ◽  
Regulatory Gene ◽  
Functional Characterization

scholarly journals Genetic and mutational characterization of the small alarmone synthetase gene relV of Vibrio cholerae

Microbiology ◽  
2014 ◽  
Vol 160 (9) ◽  
pp. 1855-1866 ◽  
Author(s):  
Shreya Dasgupta ◽  
Pallabi Basu ◽  
Ritesh Ranjan Pal ◽  
Satyabrata Bag ◽  
Rupak K. Bhadra
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Small Molecules ◽  
Vibrio Cholerae ◽  
Stringent Response ◽  
Synthetase Activity ◽  
Gram Negative Bacteria ◽  
Amino Acid Residues ◽  
Gram Negative

In Vibrio cholerae, the causative agent of cholera, products of three genes, relA, spoT and relV, govern nutritional stress related stringent response (SR). SR in bacteria is critically regulated by two intracellular small molecules, guanosine 3′-diphosphate 5′-triphosphate (pppGpp) and guanosine 3′,5′-bis(diphosphate) (ppGpp), collectively called (p)ppGpp or alarmone. Evolution of relV is unique in V. cholerae because other Gram-negative bacteria carry only relA and spoT genes. Recent reports suggest that RelV is needed for pathogenesis. RelV carries a single (p)ppGpp synthetase or RelA-SpoT domain (SYNTH/RSD) and belongs to the small alarmone synthetase (SAS) family of proteins. Here, we report extensive functional characterizations of the relV gene by constructing several deletion and site-directed mutants followed by their controlled expression in (p)ppGpp0 cells of Escherichia coli or V. cholerae. Substitution analysis indicated that the amino acid residues K107, D129, R132, L150 and E188 of the RSD region of RelV are essential for its activity. While K107, D129 and E188 are highly conserved in RelA and SAS proteins, L150 appears to be conserved in the latter group of enzymes, and the R132 residue was found to be unique in RelV. Extensive progressive deletion analysis indicated that the amino acid residues at positions 59 and 248 of the RelV protein are the functional N- and C-terminal boundaries, respectively. Since the minimal functional length of RelV was found to be 189 aa, which includes the 94 aa long RSD region, it seems that the flanking residues of the RSD are also important for maintaining the (p)ppGpp synthetase activity.

scholarly journals Role of GntR Family Regulatory Gene SCO1678 in Gluconate Metabolism in Streptomyces coelicolor M145

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Olga Tsypik ◽  
Roman Makitrynskyy ◽  
Agnieszka Bera ◽  
Lijiang Song ◽  
Wolfgang Wohlleben ◽  
...  
Keyword(s):  
Antibiotic Production ◽  
Streptomyces Coelicolor ◽  
Regulatory Gene ◽  
Functional Characterization ◽  
Bioinformatic Analysis ◽  
Transcriptional Analysis ◽  
Dependent Manner ◽  
Putative Operon

Here we report functional characterization of the Streptomyces coelicolor M145 gene SCO1678, which encodes a GntR-like regulator of the FadR subfamily. Bioinformatic analysis suggested that SCO1678 is part of putative operon (gnt) involved in gluconate metabolism. Combining the results of SCO1678 knockout, transcriptional analysis of gnt operon, and Sco1678 protein-DNA electromobility shift assays, we established that Sco1678 protein controls the gluconate operon. It does so via repression of its transcription from a single promoter located between genes SCO1678 and SCO1679. The knockout also influenced, in a medium-dependent manner, the production of secondary metabolites by S. coelicolor. In comparison to the wild type, on gluconate-containing minimal medium, the SCO1678 mutant produced much less actinorhodin and accumulated a yellow-colored pigment, likely to be the cryptic polyketide coelimycin. Possible links between gluconate metabolism and antibiotic production are discussed.

Structural and Functional Characterization of IS1358 from Vibrio cholerae

1998 ◽  
Vol 180 (23) ◽  
pp. 6101-6106
Author(s):  
Sandrine Dumontier ◽  
Patrick Trieu-Cuot ◽  
Patrick Berche
Keyword(s):  
Vibrio Cholerae ◽  
Functional Characterization

scholarly journals Identification and characterization of the Streptomyces globisporus 1912 regulatory gene lndYR that affects sporulation and antibiotic production

Microbiology ◽  
2011 ◽  
Vol 157 (4) ◽  
pp. 1240-1249 ◽  
Author(s):  
Bohdan Ostash ◽  
Yuriy Rebets ◽  
Maksym Myronovskyy ◽  
Olga Tsypik ◽  
Iryna Ostash ◽  
...  
Keyword(s):  
Antibiotic Production ◽  
Streptomyces Coelicolor ◽  
Regulatory Gene ◽  
Functional Characterization ◽  
Signal Features ◽  
Abc Transporter Genes ◽  
Identification And Characterization

Here, we report the identification and functional characterization of the Streptomyces globisporus 1912 gene lndYR, which encodes a GntR-like regulator of the YtrA subfamily. Disruption of lndYR arrested sporulation and antibiotic production in S. globisporus. The results of in vivo and in vitro studies revealed that the ABC transporter genes lndW–lndW2 are targets of LndYR repressive action. In Streptomyces coelicolor M145, lndYR overexpression caused a significant increase in the amount of extracellular actinorhodin. We suggest that lndYR controls the transcription of transport system genes in response to an as-yet-unidentified signal. Features that distinguish lndYR-based regulation from other known regulators are discussed.

scholarly journals Structural and functional characterization of CMP-N-acetylneuraminate synthetase fromVibrio cholerae

2019 ◽  
Vol 75 (6) ◽  
pp. 564-577
Author(s):  
Sucharita Bose ◽  
Debayan Purkait ◽  
Deepthi Joseph ◽  
Vinod Nayak ◽  
Ramaswamy Subramanian
Keyword(s):  
Sialic Acid ◽  
Vibrio Cholerae ◽  
Active Site ◽  
Drug Targets ◽  
Pathogenic Bacteria ◽  
Pasteurella Multocida ◽  
Bacterial Species ◽  
Functional Characterization ◽  
Gut Colonization

Several pathogenic bacteria utilize sialic acid, including host-derivedN-acetylneuraminic acid (Neu5Ac), in at least two ways: they use it as a nutrient source and as a host-evasion strategy by coating themselves with Neu5Ac. Given the significant role of sialic acid in pathogenesis and host-gut colonization by various pathogenic bacteria, includingNeisseria meningitidis,Haemophilus influenzae,Pasteurella multocidaandVibrio cholerae, several enzymes of the sialic acid catabolic, biosynthetic and incorporation pathways are considered to be potential drug targets. In this work, findings on the structural and functional characterization of CMP-N-acetylneuraminate synthetase (CMAS), a key enzyme in the incorporation pathway, fromVibrio choleraeare reported. CMAS catalyzes the synthesis of CMP-sialic acid by utilizing CTP and sialic acid. Crystal structures of the apo and the CDP-bound forms of the enzyme were determined, which allowed the identification of the metal cofactor Mg2+in the active site interacting with CDP and the invariant Asp215 residue. While open and closed structural forms of the enzyme from eukaryotic and other bacterial species have already been characterized, a partially closed structure ofV. choleraeCMAS (VcCMAS) observed upon CDP binding, representing an intermediate state, is reported here. The kinetic data suggest that VcCMAS is capable of activating the two most common sialic acid derivatives, Neu5Ac and Neu5Gc. Amino-acid sequence and structural comparison of the active site of VcCMAS with those of eukaryotic and other bacterial counterparts reveal a diverse hydrophobic pocket that interacts with the C5 substituents of sialic acid. Analyses of the thermodynamic signatures obtained from the binding of the nucleotide (CTP) and the product (CMP-sialic acid) to VcCMAS provide fundamental information on the energetics of the binding process.

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