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 ◽  
...  

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.

1991 ◽  
Vol 69 (5) ◽  
pp. 1040-1052 ◽  
Author(s):  
R. Michael L. McKay ◽  
Sarah P. Gibbs

At present, little physiological or biochemical data exist for pyrenoids mainly because isolation of intact pyrenoids using standard cell-fractionation methodology has met with only limited success. Techniques of microscopical cytochemistry and immunocytochemistry, however, readily lend themselves to the in situ investigation of pyrenoid composition. Immunocytochemical analyses have demonstrated that in evolutionarily diverse groups of pyrenoid-containing algae and hornworts, the Calvin cycle enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is predominantly pyrenoid-localized. Moreover, the localization of Rubisco activase to pyrenoids of green algae and hornworts indicates that pyrenoid-localized Rubisco is catalytically competent. Although pyrenoids are reported to contain polypeptides other than Rubisco and Rubisco activase, none have been identified with certainty. The exclusion of phosphoribulokinase from the pyrenoids of red and green algae indicates that pyrenoids do not possess the full complement of Calvin cycle enzymes. There have been reports that nitrate reductase is pyrenoid-localized in green algae; however, this remains a contentious issue. Why Rubisco is localized to the pyrenoid is not clear. Available evidence does not support the extension to pyrenoids of a model recently devised for cyanobacterial carboxysomes in which the carboxysome is identified as an integral component of the inorganic carbon concentrating mechanism. Instead, perhaps the pyrenoid represents an evolutionary intermediate between cyanobacterial carboxysomes and the condition in which Rubisco is distributed throughout the chloroplast stroma. Key words: algae, hornworts, immunocytochemistry, chloroplast, pyrenoid, Rubisco.


2018 ◽  
Vol 115 (49) ◽  
pp. E11455-E11464 ◽  
Author(s):  
Devin L. Trudeau ◽  
Christian Edlich-Muth ◽  
Jan Zarzycki ◽  
Marieke Scheffen ◽  
Moshe Goldsmith ◽  
...  

Photorespiration recycles ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) oxygenation product, 2-phosphoglycolate, back into the Calvin Cycle. Natural photorespiration, however, limits agricultural productivity by dissipating energy and releasing CO2. Several photorespiration bypasses have been previously suggested but were limited to existing enzymes and pathways that release CO2. Here, we harness the power of enzyme and metabolic engineering to establish synthetic routes that bypass photorespiration without CO2 release. By defining specific reaction rules, we systematically identified promising routes that assimilate 2-phosphoglycolate into the Calvin Cycle without carbon loss. We further developed a kinetic–stoichiometric model that indicates that the identified synthetic shunts could potentially enhance carbon fixation rate across the physiological range of irradiation and CO2, even if most of their enzymes operate at a tenth of Rubisco’s maximal carboxylation activity. Glycolate reduction to glycolaldehyde is essential for several of the synthetic shunts but is not known to occur naturally. We, therefore, used computational design and directed evolution to establish this activity in two sequential reactions. An acetyl-CoA synthetase was engineered for higher stability and glycolyl-CoA synthesis. A propionyl-CoA reductase was engineered for higher selectivity for glycolyl-CoA and for use of NADPH over NAD+, thereby favoring reduction over oxidation. The engineered glycolate reduction module was then combined with downstream condensation and assimilation of glycolaldehyde to ribulose 1,5-bisphosphate, thus providing proof of principle for a carbon-conserving photorespiration pathway.


1984 ◽  
Vol 11 (6) ◽  
pp. 509 ◽  
Author(s):  
H Usuda ◽  
MSB Ku ◽  
GE Edwards

Among 10 C4 species having a wide range in photosynthetic activity, the rates of photosynthesis/leaf area under high light were examined and compared with the chlorophyll and soluble protein content and the activities of several photosynthetic enzymes. The species examined were Digitaria sanguinalis, Echinochloa crus-galli, Microstegium vimineum, Panicum capillare, Panicum miliaceum, Paspalum dilatatum, Paspalum notatum, Pennisetum purpureum, Setaria lutescens, and Zea mays. The photosynthetic rates per unit leaf area ranged from 10 to 38 �mol CO2 fixed m-2 s-1. Among the 10 species there was a high degree of correlation of rate of photosynthesis/leaf area with soluble protein (r = 0.88), ribulose 1,5-bisphosphate carboxylase (r = 0.88) and pyruvate,PI dikinase (r = 0.94), but a lower correlation of photosynthetic rate/leaf area with phosphoenolpyruvate carboxylase (r = 0.74) and no significant correlation of photosynthetic rate/leaf area with chlorophyll content (r = 0.56). Among eight species of the NADP-malic enzyme C4 subgroup, there was a good correlation of photosynthetic ratelleaf area with NADP-malate dehydrogenase (r = 0.88) and NADP- malic enzyme (r = 0.92). Extractable activities of both the ribulose 1,5-bisphosphate carboxylase and the dikinase were generally close to the rate of photosynthesis. When comparing the activity per unit leaf area of one enzyme with another, generally a high degree of correlation was found among the species. The results suggest that a given C4 species tends to maintain a balance in the activities of several photosynthetic enzymes and that there is potential to estimate capacity for C4 photosynthesis under high light through determining activity of certain photosynthetic enzymes.


2004 ◽  
Vol 129 (5) ◽  
pp. 738-744 ◽  
Author(s):  
Li-Song Chen ◽  
Brandon R. Smith ◽  
Lailiang Cheng

Own-rooted 1-year-old `Concord' grapevines (Vitis labruscana Bailey) were fertigated twice weekly for 11 weeks with 1, 10, 20, 50, or 100 μm iron (Fe) from ferric ethylenediamine di (o-hydroxyphenylacetic) acid (Fe-EDDHA) in a complete nutrient solution. As Fe supply increased, leaf total Fe content did not show a significant change, whereas active Fe (extracted by 2,2′-dipyridyl) content increased curvilinearly. Chlorophyll (Chl) content increased as Fe supply increased, with a greater response at the lower Fe rates. Chl a: b ratio remained relatively constant over the range of Fe supply, except for a slight increase at the lowest Fe treatment. Both CO2 assimilation and stomatal conductance increased curvilinearly with increasing leaf active Fe, whereas intercellular CO2 concentrations decreased linearly. Activities of key enzymes in the Calvin cycle, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), NADP-glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoribulokinase (PRK), stromal fructose-1,6-bisphosphatase (FBPase), and a key enzyme in sucrose synthesis, cytosolic FBPase, all increased linearly with increasing leaf active Fe. No significant difference was found in the activities of ADP-glucose pyrophosphorylase (AGPase) and sucrose phosphate synthase (SPS) of leaves between the lowest and the highest Fe treatments, whereas slightly lower activities of AGPase and SPS were observed in the other three Fe treatments. Content of 3-phosphoglycerate (PGA) increased curvilinearly with increasing leaf active Fe, whereas glucose-6-phosphate (G6P), fructose-6-phosphate (F6P), and the ratio of G6P: F6P remained unchanged over the range of Fe supply. Concentrations of glucose, fructose, sucrose, starch, and total nonstructural carbohydrates (TNC) at both dusk and predawn increased with increasing leaf active Fe. Concentrations of starch and TNC at any given leaf active Fe content were higher at dusk than at predawn, but both glucose and fructose showed the opposite trend. No difference in sucrose concentration was found at dusk or predawn. The export of carbon from starch breakdown during the night, calculated as the difference between dusk and predawn measurements, increased as leaf active Fe content increased. The ratio of starch to sucrose at both dusk and predawn also increased with increasing leaf active Fe. In conclusion, Fe limitation reduces the activities of Rubisco and other photosynthetic enzymes, and hence CO2 assimilation capacity. Fe-deficient grapevines have lower concentrations of nonstructural carbohydrates in source leaves and, therefore, are source limited.


1989 ◽  
Vol 9 (5) ◽  
pp. 2279-2283
Author(s):  
S Jindal ◽  
A K Dudani ◽  
B Singh ◽  
C B Harley ◽  
R S Gupta

The complete cDNA for a human mitochondrial protein designated P1, which was previously identified as a microtubule-related protein, has been cloned and sequenced. The deduced amino acid sequence of P1 shows strong homology (40 to 50% identical residues and an additional 20% conservative replacements) to the 65-kilodalton major antigen of mycobacteria, to the GroEL protein of Escherichia coli, and to the ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) subunit binding protein of plant chloroplasts. Similar to the case with the latter two proteins, which have been shown to act as chaperonins in the posttranslational assembly of oligomeric protein structures, it is suggested that P1 may play a similar role in mammalian cells. The observed high degree of homology between human P1 and mycobacterial antigen also suggests the possible involvement of this protein in certain autoimmune diseases.


1991 ◽  
Vol 275 (3) ◽  
pp. 629-633 ◽  
Author(s):  
N Franceschini ◽  
G Amicosante ◽  
M Perilli ◽  
M Maccarrone ◽  
A Oratore ◽  
...  

The N-terminal sequences of the two major beta-lactamases produced by Citrobacter diversus differed only by the absence of the first residue in form II and the loss of five amino acid residues at the C-terminal end. Limited proteolysis of the homogeneous form I protein yielded a variety of enzymatically active products. In the major product obtained after the action of papain, the first three N-terminal residues of form I had been cleaved, whereas at the C-terminal end the treated enzyme lacked five residues. However, this cannot explain the different behaviours of form I, form II and papain digestion product upon chromatofocusing. Form I, which was sequenced up to position 56, exhibited a very high degree of similarity with a Klebsiella oxytoca beta-lactamase. The determined sequence, which contained the active serine residue, demonstrated that the chromosome-encoded beta-lactamase of Citrobacter diversus belong to class A.


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