Identification of residues important for NAD+ binding by the Thermotoga maritima alpha-glucosidase AglA, a member of glycoside hydrolase family 4.
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Raasch C, Armbrecht M, Streit W, Hocker B, Strater N, Liebl W
Identification of residues important for NAD+ binding by the Thermotoga maritima alpha-glucosidase AglA, a member of glycoside hydrolase family 4.
FEBS Lett. 2002 Apr 24;517(1-3):267-71.
- PubMed ID
- 12062450 [ View in PubMed]
- Abstract
The NAD+-requiring enzymes of glycoside hydrolase family 4 (GHF4) contain a region with a conserved Gly-XXX-Gly-Ser (GXGS) motif near their N-termini that is reminiscent of the fingerprint region of the Rossmann fold, a conserved structural motif of classical nicotinamide nucleotide-binding proteins. The function of this putative NAD+-binding motif in the alpha-glucosidase AglA of Thermotoga maritima was probed by directed mutagenesis. The K(d) for NAD+ of the AglA mutants G10A, G12A and S13A was increased by about 300-, 5-, and 9-fold, respectively, while their K(m) for p-nitrophenyl-alpha-glucopyranoside was not seriously affected. The results indicate that the GXGS motif is indeed important for NAD+ binding by the glycosidases of GHF4.