scholarly journals Occurrence, phylogeny and evolution of ribulose-1,5-bisphosphate carboxylase/oxygenase genes in obligately chemolithoautotrophic sulfur-oxidizing bacteria of the genera Thiomicrospira and Thioalkalimicrobium

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2159-2169 ◽  
Author(s):  
Tatjana P. Tourova ◽  
Elizaveta M. Spiridonova ◽  
Ivan A. Berg ◽  
Boris B. Kuznetsov ◽  
Dimitry Yu. Sorokin

The occurrence of the different genes encoding ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), the key enzyme of the Calvin–Benson–Bassham cycle of autotrophic CO2 fixation, was investigated in the members of the genus Thiomicrospira and the relative genus Thioalkalimicrobium, all obligately chemolithoautotrophic sulfur-oxidizing Gammaproteobacteria. The cbbL gene encoding the ‘green-like’ form I RubisCO large subunit was found in all analysed species, while the cbbM gene encoding form II RubisCO was present only in Thiomicrospira species. Furthermore, species belonging to the Thiomicrospira crunogena 16S rRNA-based phylogenetic cluster also possessed two genes of green-like form I RubisCO, cbbL-1 and cbbL-2. Both 16S-rRNA- and cbbL-based phylogenies of the Thiomicrospira–Thioalkalimicrobium–Hydrogenovibrio group were congruent, thus supporting its monophyletic origin. On the other hand, it also supports the necessity for taxonomy reorganization of this group into a new family with four genera.

2007 ◽  
Vol 57 (10) ◽  
pp. 2387-2398 ◽  
Author(s):  
Tatjana P. Tourova ◽  
Elizaveta M. Spiridonova ◽  
Ivan A. Berg ◽  
Natalia V. Slobodova ◽  
Eugenia S. Boulygina ◽  
...  

The occurrence of genes encoding nitrogenase and ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) was investigated in the members of the family Ectothiorhodospiraceae. This family forms a separate phylogenetic lineage within the Gammaproteobacteria according to 16S rRNA gene sequence analysis and mostly includes photo- and chemoautotrophic halophilic and haloalkaliphilic bacteria. The cbbL gene encoding the large subunit of ‘green-like’ form I RubisCO was found in all strains, except the type strains of Alkalispirillum mobile and Arhodomonas aquaeolei. The nifH gene encoding nitrogenase reductase was present in all investigated species of the phototrophic genera Ectothiorhodospira, Halorhodospira and Thiorhodospira, but not of the genus Ectothiorhodosinus. Unexpectedly, nifH fragments were also obtained for the chemotrophic species Thioalkalispira microaerophila and Alkalilimnicola halodurans, for which diazotrophic potential has not previously been assumed. The cbbL-, nifH- and 16S rRNA gene-based trees were not highly congruent in their branching patterns since, in the ‘RubisCO’ and ‘nitrogenase’ trees, representatives of the Ectothiorhodospiraceae are divided in a number of broadly distributed clusters and branches. However, the data obtained may be regarded as evidence of the monophyletic origin of the cbbL and nifH genes in most species within the family Ectothiorhodospiraceae and mainly corresponded to the current taxonomic structure of this family. The cbbL phylogeny of the chemolithoautotrophic sulfur-oxidizers Thioalkalivibrio nitratireducens and Thioalkalivibrio paradoxus and the nitrifier Nitrococcus mobilis deviated significantly from the 16S-rRNA gene-based phylogeny. These species clustered with one of the duplicated cbbL genes of the purple sulfur bacterium Allochromatium vinosum, a member of the family Chromatiaceae.


Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 2016-2025 ◽  
Author(s):  
Tatjana P. Tourova ◽  
Olga L. Kovaleva ◽  
Dimitry Yu. Sorokin ◽  
Gerard Muyzer

The presence and diversity of the cbb genes encoding the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) (a key enzyme of the Calvin–Benson cycle of autotrophic CO2 assimilation) were investigated in pure cultures of seven genera of halophilic chemolithoautotrophic sulfur-oxidizing bacteria (SOB) and in sediments from a hypersaline lake in which such bacteria have been recently discovered. All of the halophilic SOB strains (with the exception of Thiohalomonas nitratireducens) possessed the cbbL gene encoding RuBisCO form I, while the cbbM gene encoding RuBisCO form II was detected only in some of the pure cultures. The general topologies of the CbbL/CbbM trees and the 16S rRNA gene tree were different, but both markers showed that the halophilic SOB genera formed independent lineages in the Gammaproteobacteria. In some cases, such as with several strains of the genus Thiohalospira and with Thioalkalibacter halophilus, the cbbL clustering was incongruent with the positions of these strains on the ribosomal tree. In the cbbM tree, the clustering of Thiohalospira and Thiohalorhabdus strains was incongruent with their branching in both cbbL and 16S rRNA gene trees. cbbL and cbbM genes related to those found in the analysed halophilic SOB were also detected in a sediment from a hypersaline lake in Kulunda Steppe (Russia). Most of the cbbL and cbbM genes belonged to members of the genus Thiohalorhabdus. In the cbbL clone library, sequences related to those of Halothiobacillus and Thiohalospira were detected as minor components. Some of the environmental cbbM sequences belonged to as yet unknown phylotypes, representing deep lineages of halophilic autotrophs.


1998 ◽  
Vol 336 (2) ◽  
pp. 387-393 ◽  
Author(s):  
Graeme BAINBRIDGE ◽  
P. John ANRALOJC ◽  
Pippa J. MADGWICK ◽  
Jim E. PITTS ◽  
Martin A. J. PARRY

The contribution of lysine-128 within the active site of Anacystis nidulansd-ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) was investigated by the characterization of mutants in which lysine-128 was replaced with arginine, glycine, glutamine, histidine or aspartic acid. Mutated genes encoding the Rubisco large subunit were expressed in Escherichia coliand the resultant polypeptides assembled into active complexes. All of the mutant enzymes had a lower affinity for ribulose 1,5-bisphosphate (RuBP) and lower rates of carboxylation. Substitution of lysine-128 with glutamine, histidine or aspartic acid decreased the specificity factor and led to the production of an additional monophosphate reaction product. We show that this product results from the loss of the phosphate from C-1 of RuBP, most probably by β-elimination from the 2,3-enediolate derivative of RuBP. The results confirm that lysine-128 is important in determining the position of the essential ε-amino group of lysine-334 within the active site and in loop dynamics. This further demonstrates that residues remote from the active site can be manipulated to modify catalytic function.


1998 ◽  
Vol 180 (16) ◽  
pp. 4258-4269 ◽  
Author(s):  
George C. Paoli ◽  
Padungsri Vichivanives ◽  
F. Robert Tabita

ABSTRACT The genes encoding enzymes of the Calvin-Benson-Bassham (CBB) reductive pentose phosphate pathway in Rhodobacter capsulatus are organized in at least two operons, each preceded by a separate cbbR gene, encoding potential LysR-type transcriptional activators. As a prelude to studies ofcbb gene regulation in R. capsulatus, the nucleotide sequence of a 4,537-bp region, which includedcbbR II, was determined. This region contained the following open reading frames: a partial pgmgene (encoding phosphoglucomutase) and a complete qorgene (encoding NADPH:quinone oxidoreductase), followed by cbbR II, cbbF (encoding fructose 1,6-bisphosphatase), cbbP (encoding phosphoribulokinase), and part of cbbT (encoding transketolase). Physiological control of the CBB pathway and regulation of the R. capsulatus cbb genes were studied by using a combination of mutant strains and promoter fusion constructs. Characterization of mutant strains revealed that either form I or form II ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), encoded by the cbbLS andcbbM genes, respectively, could support photoheterotrophic and autotrophic growth. A strain with disruptions in both cbbL and cbbM could not grow autotrophically and grew photoheterotrophically only when dimethyl sulfoxide was added to the culture medium. Disruption ofcbbP resulted in a strain that did not synthesize form II RubisCO and had a phenotype similar to that observed in the RubisCO-minus strain, suggesting that there is only onecbbP gene in R. capsulatus and that this gene is cotranscribed with cbbM. Analysis of RubisCO activity and synthesis in strains with disruptions in eithercbbR I orcbbR II, and β-galactosidase determinations from wild-type and mutant strains containing cbb Ip- andcbb IIp-lacZ fusion constructs, indicated that the cbb I andcbb II operons of R. capsulatus are within separate CbbR regulons.


1998 ◽  
Vol 180 (17) ◽  
pp. 4380-4386 ◽  
Author(s):  
Jan Martinussen ◽  
Karin Hammer

ABSTRACT The biosynthesis of carbamoylphosphate is catalyzed by the heterodimeric enzyme carbamoylphosphate synthetase. The genes encoding the two subunits of this enzyme in procaryotes are normally transcribed as an operon, but the gene encoding the large subunit (carB) in Lactococcus lactis is shown to be transcribed as an isolated unit. Carbamoylphosphate is a precursor in the biosynthesis of both pyrimidine nucleotides and arginine. By mutant analysis,L. lactis is shown to possess only onecarB gene; the same gene product is thus required for both biosynthetic pathways. Furthermore, arginine may satisfy the requirement for carbamoylphosphate in pyrimidine biosynthesis through degradation by means of the arginine deiminase pathway. The expression of the carB gene is subject to regulation at the level of transcription by pyrimidines, most probably by an attenuator mechanism. Upstream of the carB gene, an open reading frame showing a high degree of similarity to those of glutathione peroxidases from other organisms was identified.


2020 ◽  
Vol 8 (12) ◽  
pp. 1880
Author(s):  
Marcela Hernández ◽  
Blanca Vera-Gargallo ◽  
Marcela Calabi-Floody ◽  
Gary M. King ◽  
Ralf Conrad ◽  
...  

Microorganisms can potentially colonise volcanic rocks using the chemical energy in reduced gases such as methane, hydrogen (H2) and carbon monoxide (CO). In this study, we analysed soil metagenomes from Chilean volcanic soils, representing three different successional stages with ages of 380, 269 and 63 years, respectively. A total of 19 metagenome-assembled genomes (MAGs) were retrieved from all stages with a higher number observed in the youngest soil (1640: 2 MAGs, 1751: 1 MAG, 1957: 16 MAGs). Genomic similarity indices showed that several MAGs had amino-acid identity (AAI) values >50% to the phyla Actinobacteria, Acidobacteria, Gemmatimonadetes, Proteobacteria and Chloroflexi. Three MAGs from the youngest site (1957) belonged to the class Ktedonobacteria (Chloroflexi). Complete cellular functions of all the MAGs were characterised, including carbon fixation, terpenoid backbone biosynthesis, formate oxidation and CO oxidation. All 19 environmental genomes contained at least one gene encoding a putative carbon monoxide dehydrogenase (CODH). Three MAGs had form I coxL operon (encoding the large subunit CO-dehydrogenase). One of these MAGs (MAG-1957-2.1, Ktedonobacterales) was highly abundant in the youngest soil. MAG-1957-2.1 also contained genes encoding a [NiFe]-hydrogenase and hyp genes encoding accessory enzymes and proteins. Little is known about the Ktedonobacterales through cultivated isolates, but some species can utilise H2 and CO for growth. Our results strongly suggest that the remote volcanic sites in Chile represent a natural habitat for Ktedonobacteria and they may use reduced gases for growth.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Nina V. Kulakova ◽  
Natalia N. Denikina ◽  
Sergei I. Belikov

Sponges are permanent benthos residents which establish complex associations with a variety of microorganisms that raise interest in the nature of sponge-symbionts interactions. A molecular approach, based on the identification of the 16S rRNA and ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit genes, was applied to investigate diversity and phylogeny of bacterial phototrophs associated with four species of Lubomirskiidae in Lake Baikal. The phylogeny inferred from both genes showed three main clusters of Synechococcus associated with Baikalian sponges. One of the clusters belonged to the cosmopolitan Synechococcus rubescens group and the two other were not related to any of the assigned phylogenetic groups but placed as sister clusters to S. rubescens. These results expanded the understanding of freshwater sponge-associated photoautotroph diversity and suggested that the three phylogenetic groups of Synechococcus are common photosynthetic symbionts in Lubomirskiidae sponges.


2002 ◽  
Vol 184 (7) ◽  
pp. 1905-1915 ◽  
Author(s):  
Mary A. Tichi ◽  
F. Robert Tabita

ABSTRACT Various mutant strains were used to examine the regulation and metabolic control of the Calvin-Benson-Bassham (CBB) reductive pentose phosphate pathway in Rhodobacter capsulatus. Previously, a ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO)-deficient strain (strain SBI/II) was found to show enhanced levels of cbb I and cbb II promoter activities during photoheterotrophic growth in the presence of dimethyl sulfoxide. With this strain as the starting point, additional mutations were made in genes encoding phosphoribulokinase and transketolase and in the gene encoding the LysR-type transcriptional activator, CbbRII. These strains revealed that a product generated by phosphoribulokinase was involved in control of CbbR-mediated cbb gene expression in SBI/II. Additionally, heterologous expression experiments indicated that Rhodobacter sphaeroides CbbR responded to the same metabolic signal in R. capsulatus SBI/II and mutant strain backgrounds.


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