D-ribulose-1,5-diphosphate carboxylase and the evolution of autotrophy

McFadden, Bruce A.; Tabita, F. Robert

doi:10.1016/0303-2647(74)90002-1

Cited by 94 publications

(53 citation statements)

References 88 publications

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“…The role of the metal cofactor in the RuBP carboxylase reaction is unclear (12). Mg2+ has been shown to activate the enzyme during preincubation presumably by creating a stable ternary complex with the enzyme and HCO3 ions (2).…”

Section: Discussionmentioning

confidence: 99%

“…We cautiously suggest that this may be part of the explanation for the rather large differences in in vivo and in vitro carbon isotope fractionation. Moreover, it is possible that the C02 level in the atmosphere is at nonsaturating levels for RuBP carboxylase in vivo (12). This may cause a decrease in A dissolved CO2.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, these experiments have been conducted with carboxylases having similar quaternary structure, amino acid composition, and catalytic properties (12). Presumably, reaction mechanisms and hence isotopic fractionations should not vary as greatly as the literature suggests.…”

mentioning

confidence: 99%

“…RuBP carboxylases have been isolated from procaryotic systems which vary in mol wt, structural composition, and regulatory properties. For example, when isolated and purified from the purple, nonsulfur, bacterium Rhodospirillum rubrum, the carboxylase has a mol wt of 114,000, is composed of only two large subunits, and is not regulated by the effector 6-P-gluconate (12,27). Furthermore, two structurally and catalytically distinct RuBP carboxylases have been isolated from the photosynthetic bacterium Rhodopseudomonas sphaeroides (9).…”

mentioning

confidence: 99%

“…It is also apparent that a diversity of structure may exist in the blue-green algae (28,29), similar to the bacteria (9,27); i.e. Hydrogenomonas eutropha, a chemosynthetic bacterium, has a high mol wt carboxylase similar in structure to that of the spinach enzyme (12).…”

mentioning

confidence: 99%

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Carbon Isotope Fractionation by Ribulose-1,5-Bisophosphate Carboxylase from Various Organisms

Estep¹,

Tabita²,

Parker³

et al. 1978

Plant Physiol.

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Carbon Isotope fractionaton by structurally and catalytically distinct rbulose-1,5-blspbosphate carboxylases from one eucaryotic and four procaryotic organisms has been measured under itrogen. The Spinach leaf RuBP carboxylase is a large protein having a mol wt of 557,000 and is composed of eight large subunits, mol wt 55,800, and eight small subunits, mol wt 12,000 (21, 22). RuBP carboxylases have been isolated from procaryotic systems which vary in mol wt, structural composition, and regulatory properties. For example, when isolated and purified from the purple, nonsulfur, bacterium Rhodospirillum rubrum, the carboxylase has a mol wt of 114,000, is composed of only two large subunits, and is not regulated by the effector 6-P-gluconate (12, 27). Furthermore, two structurally and catalytically distinct RuBP carboxylases have been isolated from the photosynthetic bacterium Rhodopseudomonas sphaeroides (9). Peak I carboxylase is structurally and catalytically similar to the enzyme from higher plants. Peak II carboxylase has a mol wt of 360,000 and is composed of only six large subunits. It is also apparent that a diversity of structure may exist in the blue-green algae (28,29), similar to the bacteria (9, 27); i.e. Hydrogenomonas eutropha, a chemosynthetic bacterium, has a high mol wt carboxylase similar in structure to that of the spinach enzyme (12).In this paper we have examined carbon isotope fractionation by RuBP carboxylases from spinach, R rubrum, R sphaeroides, Agmenellum quadruplicatum, and H. eutropha, for several reasons. First, we have produced a reproducible fractionation value, A dissolved C02, by carefully controlling reaction conditions and purification procedures of both the enzyme and the product phosphoglyceric acid. Second, certain reaction conditions were purposely modified to test their effects on the fractionation: NaHCO concentration, 02 level, temperature, buffer, substrate, and metal cofactors. In addition, several purification states ofeach enzyme were used in order to determine the effect on the A dissolved CO2. Moreover, in an attempt to see if enzymes of different mol wt, purity, quaternary structure, and catalytic prop-

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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