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. doi: 10.1016/s0014-5793(02)02641-8.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs / genetics
  • Amino Acid Motifs / physiology
  • Amino Acid Sequence
  • Binding Sites / genetics
  • Binding Sites / physiology
  • Conserved Sequence
  • Kinetics
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • NAD / metabolism*
  • Thermotoga maritima / enzymology*
  • Thermotoga maritima / genetics
  • alpha-Glucosidases / chemistry
  • alpha-Glucosidases / genetics
  • alpha-Glucosidases / metabolism*

Substances

  • NAD
  • alpha-Glucosidases