- Activated αβ-unsaturated aldehydes as substrate of dihydroxyacetone phosphate (DHAP)-dependent aldolases in the context of a multienzyme system
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The utility for carbon-carbon bond formation of a multienzyme system composed of recombinant dihydroxyacetone kinase (DHAK) from Citrobacter freundii, the fructose bisphosphate aldolase from rabbit muscle (RAMA) and acetate kinase (AK) for adenosine triphosphate (ATP) regeneration has been studied. Several aldehydes with great structural diversity, including three α,β-unsaturated aldehydes, have been analysed as acceptor substrates. It was found that α,β-unsaturated aldehydes bearing an electron-withdrawing group in the β position to the double bond with a trans configuration are good acceptors for RAMA in this multienzyme system. The aldol reaction proceeds with excellent D-threo enantioselectivity and the aldol adduct is obtained in good overall yield. The L-threo and D-erythro enantiomers are also accessible from rhamnulose 1-phosphate aldolase (Rha-1PA) and fuculose 1-phosphate aldolase (Fuc-1PA) catalysed reactions, respectively.
- Sanchez-Moreno, Israel,Iturrate, Laura,Doyagueez, A Elisa G.,Martinez, Juan Antonio,Fernandez-Mayoralas, Alfonso,Garcia-Junceda, Eduardo
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experimental part
p. 2967 - 2975
(2010/03/25)
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- Fructose 1,6-bisphosphate aldolase from Staphylococcus carnosus: Overexpression, structure prediction, stereoselectivity, and application in the synthesis of bicyclic sugars
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The gene for the fructose 1,6-bisphosphate aldolase from Staphylococcus carnosus (FruA(sca)) was subcloned for overexpression in Escherichia coli using the expression vector pKK223-3. An efficient, single-step purification by DEAE ion-exchange chromatography furnished the recombinant enzyme ready for synthetic applications. Sequence analysis indicated that FruA(sca) shares the overall α/β-barrel structure and most of the active site residues with the structurally well-defined FruA catalyst from rabbit muscle which signaled its functional equivalence for synthetic applications. A preparative study with generic aliphatic and hydroxylated aldehydes indeed confirmed a high level of stereoselectivity for both newly created asymmetric centers, and suggested a kinetic enantioselectivity for anionically charged 3- hydroxyaldehydes. In fact, the monomeric FruA(sca) was found to tolerate even the presence of highly reactive glutardialdehyde derivatives, which otherwise rapidly denature the rabbit muscle enzyme, and to allow their stereoselective conversion to bicyclic sugars.
- Zannetti, Maria Teresa,Walter, Christiane,Knorst, Marion,Fessner, Wolf-Dieter
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p. 1882 - 1890
(2007/10/03)
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- Fructose-1,6-diphosphate aldolase from spinach leaves, a challenger for enzymatic synthesis of ketoses
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Fructose-1,6-diphosphate aldolase is easily extracted from spinach leaves in a form sufficiently pure to be used in synthesis. Its specificity, different from that of the commercial rabbit muscle aldolase make it a new interesting tool for the synthesis of ketoses-1-phosphates.
- Valentin,Bolte
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p. 8103 - 8106
(2007/10/02)
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