2ESD

Crystal Structure of thioacylenzyme intermediate of an Nadp Dependent Aldehyde Dehydrogenase

Summary for 2ESD

• Entry DOI: 10.2210/pdb2esd/pdb
• Related: 1euh 1qi1 1qi6 2euh
• Descriptor: NADP-dependent glyceraldehyde-3-phosphate dehydrogenase, NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE, GLYCERALDEHYDE-3-PHOSPHATE, ... (4 entities in total)
• Functional Keywords: aldh, gapn, ternary complex, oxidoreductase
• Biological source: Streptococcus mutans
• Total number of polymer chains: 4
• Total formula weight: 208527.46

Authors

D'Ambrosio, K.,Didierjean, C.,Benedetti, E.,Aubry, A.,Corbier, C. (deposition date: 2005-10-26, release date: 2006-05-02, Last modification date: 2023-10-25)

Primary citation

D'Ambrosio, K.,Pailot, A.,Talfournier, F.,Didierjean, C.,Benedetti, E.,Aubry, A.,Branlant, G.,Corbier, C.
The first crystal structure of a thioacylenzyme intermediate in the ALDH family: new coenzyme conformation and relevance to catalysis
Biochemistry, 45:2978-2986, 2006

PubMed Abstract: Crystal structures of several members of the nonphosphorylating CoA-independent aldehyde dehydrogenase (ALDH) family have shown that the peculiar binding mode of the cofactor to the Rossmann fold results in a conformational flexibility for the nicotinamide moiety of the cofactor. This has been hypothesized to constitute an essential feature of the catalytic mechanism because the conformation of the cofactor required for the acylation step is not appropriate for the deacylation step. In the present study, the structure of a reaction intermediate of the E268A-glyceraldehyde 3-phosphate dehydrogenase (GAPN) from Streptococcus mutans, obtained by soaking the crystals of the enzyme/NADP complex with the natural substrate, is reported. The substrate is bound covalently in the four monomers and presents the geometric characteristics expected for a thioacylenzyme intermediate. Control experiments assessed that reduction of the coenzyme has occurred within the crystal. The structure reveals that reduction of the cofactor upon acylation leads to an extensive motion of the nicotinamide moiety with a flip of the reduced pyridinium ring away from the active site without significant changes of the protein structure. This event positions the reduced nicotinamide moiety in a pocket that likely constitutes the exit door for NADPH. Arguments are provided that the structure reported here constitutes a reasonable picture of the first thioacylenzyme intermediate characterized thus far in the ALDH family and that the position of the reduced nicotinamide moiety observed in GAPN is the one suitable for the deacylation step within all of the nonphosphorylating CoA-independent ALDH family.

PubMed: 16503652
DOI: 10.1021/bi0515117

Experimental method

X-RAY DIFFRACTION (2.55 Å)