Shifting the NAD/NADP preference in class 3 aldehyde dehydrogenase.
Among pyridine-nucleotide-dependent oxidoreductases, the class 3 family of aldehyde dehydrogenases (ALDHs) is unusual in its ability to function with either NAD or NADP. This is all the more surprising because an acidic residue, Glu140, coordinates the adenine ribose 2' hydroxyl. In many NAD-dependent dehydrogenases a similarly placed carboxylate is thought to be responsible for exclusion of NADP. The corresponding residue in most (approximately 71%) sequences in the ALDH extended family is also Glu, and most of these are NAD-specific enzymes. Site-directed mutagenesis was performed on this residue in rat class 3 ALDH. Our results indicate that this residue contributes to tighter binding of NAD in the native enzyme, but suggest that additional factors must contribute to the ability to utilize NADP. Mutagenesis of an adjacent basic residue (Lys137) indicates that it is even more essential for binding both coenzymes, consistent with its conservation in nearly all ALDHs (> 98%).
Perozich
J
J
Department of Biological Sciences, University of Pittsburgh, PA, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, USA.
Kuo
I
I
Wang
B C
BC
Boesch
J S
JS
Lindahl
R
R
Hempel
J
J
D000444:Aldehyde Dehydrogenase / Q000737:chemistry* / Q000145:classification / Q000378:metabolism*; D019943:Amino Acid Substitution; D000818:Animals; D001665:Binding Sites; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D016297:Mutagenesis, Site-Directed; D009243:NAD / Q000737:chemistry / Q000378:metabolism*; D009249:NADP / Q000737:chemistry / Q000378:metabolism*; D017433:Protein Structure, Secondary; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
D011994:Recombinant Proteins; D009243:NAD; D009249:NADP; D000444:Aldehyde Dehydrogenase