Structure of the starch-debranching enzyme barley limit dextrinase reveals homology of the N-terminal domain to CBM21

Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Sep 1;68(Pt 9):1008-12. doi: 10.1107/S1744309112031004. Epub 2012 Aug 29.

Abstract

Barley limit dextrinase (HvLD) is a debranching enzyme from glycoside hydrolase family 13 subfamily 13 (GH13_13) that hydrolyses α-1,6-glucosidic linkages in limit dextrins derived from amylopectin. The structure of HvLD was solved and refined to 1.9 Å resolution. The structure has a glycerol molecule in the active site and is virtually identical to the structures of HvLD in complex with the competitive inhibitors α-cyclodextrin and β-cyclodextrin solved to 2.5 and 2.1 Å resolution, respectively. However, three loops in the N-terminal domain that are shown here to resemble carbohydrate-binding module family 21 were traceable and were included in the present HvLD structure but were too flexible to be traced and included in the structures of the two HvLD-inhibitor complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Glycoside Hydrolases / chemistry*
  • Glycoside Hydrolases / metabolism
  • Hordeum / enzymology*
  • Models, Molecular
  • Protein Structure, Tertiary
  • Starch / chemistry
  • Starch / metabolism
  • Structural Homology, Protein*
  • Substrate Specificity

Substances

  • Starch
  • Glycoside Hydrolases
  • pullulanase

Associated data

  • PDB/4AIO