scholarly journals The Calvin cycle enzyme phosphoglycerate kinase of Xanthobacter flavus required for autotrophic CO2 fixation is not encoded by the cbb operon.

1994 ◽  
Vol 176 (19) ◽  
pp. 6120-6126 ◽  
Author(s):  
W G Meijer
Keyword(s):  
Co2 Fixation ◽  
Calvin Cycle ◽  
Phosphoglycerate Kinase ◽  
Autotrophic Co2 Fixation ◽  
Cycle Enzyme ◽  
Xanthobacter Flavus

scholarly journals The LysR-Type Transcriptional Regulator CbbR Controlling Autotrophic CO2 Fixation by Xanthobacter flavus Is an NADPH Sensor

1998 ◽  
Vol 180 (6) ◽  
pp. 1411-1417 ◽  
Author(s):  
G. van Keulen ◽  
L. Girbal ◽  
E. R. E. van den Bergh ◽  
L. Dijkhuizen ◽  
W. G. Meijer
Keyword(s):  
Dna Binding ◽  
Inorganic Compounds ◽  
Calvin Cycle ◽  
Transcriptional Regulator ◽  
Binding Assays ◽  
Autotrophic Co2 Fixation ◽  
Binding Characteristics ◽  
Xanthobacter Flavus

ABSTRACT Autotrophic growth of Xanthobacter flavus is dependent on the fixation of carbon dioxide via the Calvin cycle and on the oxidation of simple organic and inorganic compounds to provide the cell with energy. Maximal induction of the cbb andgap-pgk operons encoding enzymes of the Calvin cycle occurs in the absence of multicarbon substrates and the presence of methanol, formate, hydrogen, or thiosulfate. The LysR-type transcriptional regulator CbbR regulates the expression of the cbb andgap-pgk operons, but it is unknown to what cellular signal CbbR responds. In order to study the effects of low-molecular-weight compounds on the DNA-binding characteristics of CbbR, the protein was expressed in Escherichia coli and subsequently purified to homogeneity. CbbR of X. flavus is a dimer of 36-kDa subunits. DNA-binding assays suggested that two CbbR molecules bind to a 51-bp DNA fragment on which two inverted repeats containing the LysR motif are located. The addition of 200 μM NADPH, but not NADH, resulted in a threefold increase in DNA binding. The apparentK d NADPH of CbbR was determined to be 75 μM. By using circular permutated DNA fragments, it was shown that CbbR introduces a 64° bend in the DNA. The presence of NADPH in the DNA-bending assay resulted in a relaxation of the DNA bend by 9°. From the results of these in vitro experiments, we conclude that CbbR responds to NADPH. The in vivo regulation of the cbb andgap-pgk operons may therefore be regulated by the intracellular concentration of NADPH.

scholarly journals Genetic engineering of the Calvin cycle toward enhanced photosynthetic CO2 fixation in microalgae

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Bo Yang ◽  
Jin Liu ◽  
Xiaonian Ma ◽  
Bingbing Guo ◽  
Bin Liu ◽  
...  
Keyword(s):  
Genetic Engineering ◽  
Co2 Fixation ◽  
Calvin Cycle

Sequence homologs of the carboxysomal polypeptide CsoS1 of the thiobacilli are present in cyanobacteria and enteric bacteria that form carboxysomes - polyhedral bodies

1998 ◽  
Vol 76 (6) ◽  
pp. 906-916 ◽  
Author(s):  
J M Shively ◽  
C E Bradburne ◽  
H C Aldrich ◽  
T A Bobik ◽  
J L Mehlman ◽  
...  
Keyword(s):  
Klebsiella Oxytoca ◽  
Calvin Cycle ◽  
Enteric Bacteria ◽  
Bisphosphate Carboxylase ◽  
Cycle Enzyme ◽  
Synechococcus Sp ◽  
Positive Hybridization ◽  
Thiobacillus Neapolitanus ◽  
High Degree ◽  
Polyhedral Bodies

Carboxysomes containing the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) have been demonstrated in a variety of chemoautotrophic prokaryotes and cyanobacteria. The genes in the ccm and cso operon in Synechococcus sp. PCC7942 and Thiobacillus neapolitanus, respectively, code for several carboxysome polypeptides. The polypeptides CcmK and CsoS1 exhibit a high degree of conservation, and in turn show significant homology to the CchA and PduA polypeptides of the ethanolamine and propanediol operons of enteric bacteria. Probing Southern blots of Escherichia coli genomic DNA with csoS1A showed positive hybridization indicating the presence of a csoS1-like gene. Growing Salmonella enterica and Klebsiella oxytoca with propanediol, and E.coli with ethanolamine as the energy source under anaerobic conditions resulted in the formation of polyhedral bodies in these bacteria. The DNA - deduced amino acid sequence of three additional csoS1 genes in both Thiobacillus intermedius and Thiobacillus denitrificans was determined. The nine CsoS1 polypeptides, which includes the three previously determined for T.neapolitanus, exhibited greater than 67% sequence identity. Identity and similarity comparisons and phylogenetic analysis of known polyhedral body CsoS1-like polypeptides indicate a close structural relationship between polyhedral bodies of potentially very different function.Key words: polyhedral bodies, carboxysomes, ribulose-1,5-bisphosphate carboxylase-oxygenase, cyanobacteria, thiobacilli, enteric bacteria.

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