Exopolysaccharide (EPS) synthesis in Bradyrhizobium japonicum : sequence, operon structure and mutational analysis of an exo gene cluster

1998 ◽  
Vol 259 (2) ◽  
pp. 161-171 ◽  
Author(s):  
B. U. Becker ◽  
K. Kosch ◽  
M. Parniske ◽  
P. Müller
Keyword(s):  
Gene Cluster ◽  
Bradyrhizobium Japonicum ◽  
Mutational Analysis ◽  
Operon Structure

The Bradyrhizobium japonicum coxWXYZ gene cluster encodes a bb3-type ubiquinol oxidase

Gene ◽  
1996 ◽  
Vol 183 (1-2) ◽  
pp. 201-206 ◽  
Author(s):  
Marci Ann Surpin ◽  
Mathias Lübben ◽  
Robert J. Maier
Keyword(s):  
Gene Cluster ◽  
Bradyrhizobium Japonicum ◽  
Ubiquinol Oxidase

The complete denitrification pathway of the symbiotic, nitrogen-fixing bacterium Bradyrhizobium japonicum

2005 ◽  
Vol 33 (1) ◽  
pp. 141-144 ◽  
Author(s):  
E.J. Bedmar ◽  
E.F. Robles ◽  
M.J. Delgado
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Bradyrhizobium Japonicum ◽  
Mutational Analysis ◽  
Control Level ◽  
Gene Clusters ◽  
Alternative Form ◽  
Nitrate Respiration ◽  
Regulatory Cascade ◽  
Denitrification Genes

Denitrification is an alternative form of respiration in which bacteria sequentially reduce nitrate or nitrite to nitrogen gas by the intermediates nitric oxide and nitrous oxide when oxygen concentrations are limiting. In Bradyrhizobium japonicum, the N2-fixing microsymbiont of soya beans, denitrification depends on the napEDABC, nirK, norCBQD, and nosRZDFYLX gene clusters encoding nitrate-, nitrite-, nitric oxide- and nitrous oxide-reductase respectively. Mutational analysis of the B. japonicum nap genes has demonstrated that the periplasmic nitrate reductase is the only enzyme responsible for nitrate respiration in this bacterium. Regulatory studies using transcriptional lacZ fusions to the nirK, norCBQD and nosRZDFYLX promoter region indicated that microaerobic induction of these promoters is dependent on the fixLJ and fixK2 genes whose products form the FixLJ–FixK2 regulatory cascade. Besides FixK2, another protein, nitrite and nitric oxide respiratory regulator, has been shown to be required for N-oxide regulation of the B. japonicum nirK and norCBQD genes. Thus nitrite and nitric oxide respiratory regulator adds to the FixLJ–FixK2 cascade an additional control level which integrates the N-oxide signal that is critical for maximal induction of the B. japonicum denitrification genes. However, the identity of the signalling molecule and the sensing mechanism remains unknown.

scholarly journals Characterization of the Biosynthesis Gene Cluster for the Pyrrole Polyether Antibiotic Calcimycin (A23187) inStreptomyces chartreusisNRRL 3882

2010 ◽  
Vol 55 (3) ◽  
pp. 974-982 ◽  
Author(s):  
Qiulin Wu ◽  
Jingdan Liang ◽  
Shuangjun Lin ◽  
Xiufen Zhou ◽  
Linquan Bai ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Mutational Analysis ◽  
Divalent Cations ◽  
Biological Effects ◽  
Biosynthetic Gene Cluster ◽  
Type I ◽  
Biosynthesis Gene Cluster ◽  
Biosynthesis Gene ◽  
Hydroxyanthranilic Acid

ABSTRACTThe pyrrole polyether antibiotic calcimycin (A23187) is a rare ionophore that is specific for divalent cations. It is widely used as a biochemical and pharmacological tool because of its multiple, unique biological effects. Here we report on the cloning, sequencing, and mutational analysis of the 64-kb biosynthetic gene cluster fromStreptomyces chartreusisNRRL 3882. Gene replacements confirmed the identity of the gene cluster, andin silicoanalysis of the DNA sequence revealed 27 potential genes, including 3 genes for the biosynthesis of the α-ketopyrrole moiety, 5 genes that encode modular type I polyketide synthases for the biosynthesis of the spiroketal ring, 4 genes for the biosynthesis of 3-hydroxyanthranilic acid, anN-methyltransferase tailoring gene, a resistance gene, a type II thioesterase gene, 3 regulatory genes, 4 genes with other functions, and 5 genes of unknown function. We propose a pathway for the biosynthesis of calcimycin and assign the genes to the biosynthesis steps. Our findings set the stage for producing much desired calcimycin derivatives using genetic modification instead of chemical synthesis.

scholarly journals Organizational and Mutational Analysis of a Complete FR-008/Candicidin Gene Cluster Encoding a Structurally Related Polyene Complex

2003 ◽  
Vol 10 (11) ◽  
pp. 1065-1076 ◽  
Author(s):  
Shi Chen ◽  
Xi Huang ◽  
Xiufen Zhou ◽  
Linquan Bai ◽  
Jing He ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Mutational Analysis
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