Crystal Structure of Two Ternary Complexes of Phosphorylating Glyceraldehyde-3-phosphate Dehydrogenase fromBacillus stearothermophiluswith NAD and d-Glyceraldehyde 3-Phosphate

Claude Didierjean, Catherine Corbier, Mustapha Fatih, Frédérique Favier, Sandrine Boschi-Muller, Guy Branlant, André Aubry
2003 Journal of Biological Chemistry  
The crystal structure of the phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Bacillus stearothermophilus was solved in complex with its cofactor, NAD, and its physiological substrate, D-glyceraldehyde 3-phosphate (D-G3P). To isolate a stable ternary complex, the nucleophilic residue of the active site, Cys 149 , was substituted with alanine or serine. The C149A and C149S GAPDH ternary complexes were obtained by soaking the crystals of the corresponding binary complexes
more » ... inary complexes (enzyme⅐NAD) in a solution containing G3P. The structures of the two binary and the two ternary complexes are presented. The D-G3P adopts the same conformation in the two ternary complexes. It is bound in a non-covalent way, in the free aldehyde form, its C-3 phosphate group being positioned in the P s site and not in the P i site. Its C-1 carbonyl oxygen points toward the essential His 176 , which supports the role proposed for this residue along the two steps of the catalytic pathway. Arguments are provided that the structures reported here are representative of a productive enzyme⅐NAD⅐D-G3P complex in the ground state (Michaelis complex).
doi:10.1074/jbc.m211040200 pmid:12569100 fatcat:ebe4h7v2rbas7nvm3zltiz6wmy