PortEco logo


From EcoliWiki
Jump to: navigation, search



Schneider, S, Gutiérrez, M, Sandalova, T, Schneider, G, Clapés, P, Sprenger, GA and Samland, AK (2010) Redesigning the active site of transaldolase TalB from Escherichia coli: new variants with improved affinity towards nonphosphorylated substrates. Chembiochem 11:681-90


Recently, we reported on a transaldolase B variant (TalB F178Y) that is able to use dihydroxyacetone (DHA) as donor in aldol reactions. In a second round of protein engineering, we aimed at improving the affinity of this variant towards nonphosphorylated acceptor aldehydes, that is, glyceraldehyde (GA). The anion binding site was identified in the X-ray structure of TalB F178Y where a sulfate ion from the buffer was bound in the active site. Therefore, we performed site-directed saturation mutagenesis at three residues forming the putative phosphate binding site, Arg181, Ser226 and Arg228. The focused libraries were screened for the formation of D-fructose from DHA and d,l-GA by using an adjusted colour assay. The best results with respect to the synthesis of D-fructose were achieved with the TalB F178Y/R181E variant, which exhibited an at least fivefold increase in affinity towards d,l-GA (K(M)=24 mM). We demonstrated that this double mutant can use D-GA, glycolaldehyde and the L-isomer, L-GA, as acceptor substrates. This resulted in preparative synthesis of D-fructose, D-xylulose and L-sorbose when DHA was used as donor. Hence, we engineered a DHA-dependent aldolase that can synthesise the formation of polyhydroxylated compounds from simple and cheap substrates at preparative scale.


PubMed Online version:10.1002/cbic.200900720


Amino Acid Substitution; Binding Sites; Biocatalysis; Catalytic Domain; Crystallography, X-Ray; Dihydroxyacetone/chemistry; Escherichia coli/enzymology; Fructose/biosynthesis; Mutagenesis, Site-Directed; Protein Engineering; Substrate Specificity; Transaldolase/chemistry; Transaldolase/genetics; Transaldolase/metabolism


You can help EcoliWiki by summarizing why this paper is useful

Useful Materials and Methods

You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.


Gene product Qualifier GO ID GO term name Evidence Code with/from Aspect Notes Status

EcoliWiki Links

Add links to pages that link here (e.g. gene, product, method pages)

See also


See Help:References for how to manage references in EcoliWiki.