The large subunit determines catalytic specificity of barley sucrose:fructan 6-fructosyltransferase and fescue sucrose:sucrose 1-fructosyltransferase

FEBS Lett. 2004 Jun 4;567(2-3):214-8. doi: 10.1016/j.febslet.2004.04.064.

Abstract

Plant fructosyltransferases are highly homologous in primary sequence and typically consist of two subunits but catalyze widely different reactions. Using functional expression in the yeast Pichia pastoris, we show that the substrate specificity of festuca sucrose:sucrose 1--beta-D-fructosyltransferase (1-SST) and barley sucrose:fructan 6--beta-D-fructosyltransferase (6-SFT) is entirely determined by the large subunit. Chimeric enzymes with the large subunit of festuca 1-SST (LSuB) and the small subunit of barley 6-SFT have the same catalytic specificity as the native festuca 1-SST and vice versa. If the LSuB is expressed alone, it does not yield a functionally active enzyme, indicating that the small subunit is nevertheless essential.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Catalysis
  • Cloning, Molecular
  • Festuca / enzymology*
  • Hexosyltransferases / chemistry*
  • Hexosyltransferases / genetics
  • Hexosyltransferases / metabolism*
  • Hordeum / enzymology*
  • Ketoses / metabolism
  • Mutagenesis
  • Oligosaccharides / metabolism
  • Pichia / genetics
  • Pichia / metabolism
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plasmids / genetics
  • Protein Subunits
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Substrate Specificity
  • Sucrose / metabolism

Substances

  • Ketoses
  • Oligosaccharides
  • Plant Proteins
  • Protein Subunits
  • Recombinant Proteins
  • fungitetraose
  • Sucrose
  • Hexosyltransferases
  • sucrose - fructan 6-fructosyltransferase
  • inulosucrase