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Preparation and Characterization of a Bifunctional Aldolase/Kinase Enzyme: A More Efficient Biocatalyst for CC Bond Formation
Author(s) -
Iturrate Laura,
SánchezMoreno Israel,
OrozGuinea Isabel,
PérezGil Jesús,
GarcíaJunceda Eduardo
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200903096
Subject(s) - phosphofructokinase 2 , aldolase a , bifunctional , fructose bisphosphate aldolase , chemistry , enzyme , circular dichroism , stereochemistry , linker , biochemistry , combinatorial chemistry , catalysis , operating system , computer science
A bifunctional aldolase/kinase enzyme named DLF has been constructed by gene fusion through overlap extension. This fusion enzyme consists of monomeric fructose‐1,6‐bisphosphate aldolase (FBPA) from Staphylococcus carnosus and the homodimeric dihydroxyacetone kinase (DHAK) from Citrobacter freundii CECT 4626 with an intervening linker of five amino acid residues. The fusion protein was expressed soluble and retained both kinase and aldolase activities. The secondary structures of the bifunctional enzyme and the parental enzymes were analyzed by circular dichroism (CD) spectroscopy to study the effect of the covalent coupling of the two parent proteins on the structure of the fused enzyme. Because S. carnosus FBPA is a thermostable protein, the effect of the fusion on the thermal stability of the bifunctional enzyme has also been studied. The proximity of the active centers in the fused enzyme promotes a kinetic advantage as the 20‐fold increment in the initial velocity of the overall aldol reaction indicates. Experimental evidence supports that this increase in the reaction rate can be explained in terms of substrate channeling.