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  • The EMBO Journal (2005) 24, 694 - 704
  • doi:10.1038/sj.emboj.7600551

Published online: 3 February 2005

Crystal structure of potato tuber ADP-glucose pyrophosphorylase

Xiangshu Jin1,2,a, Miguel A Ballicora2, Jack Preiss2 and James H Geiger1

  1. Department of Chemistry, Michigan State University, East Lansing, MI, USA
  2. Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA

Correspondence to:

James H Geiger, Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA. Tel.: +1 517 355 9715 Ext. 234; Fax: +1 517 353 1793; E-mail: geiger@cem.msu.edu

Jack Preiss, Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA. Tel.: +1 517 353 3137; Fax: +1 517 353 9334; E-mail: preiss@msu.edu

aPresent address: Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA

Received 2 August 2004; Accepted 20 December 2004

ADP-glucose pyrophosphorylase catalyzes the first committed and rate-limiting step in starch biosynthesis in plants and glycogen biosynthesis in bacteria. It is the enzymatic site for regulation of storage polysaccharide accumulation in plants and bacteria, being allosterically activated or inhibited by metabolites of energy flux. We report the first atomic resolution structure of ADP-glucose pyrophosphorylase. Crystals of potato tuber ADP-glucose pyrophosphorylase alpha subunit were grown in high concentrations of sulfate, resulting in the sulfate-bound, allosterically inhibited form of the enzyme. The N-terminal catalytic domain resembles a dinucleotide-binding Rossmann fold and the C-terminal domain adopts a left-handed parallel beta helix that is involved in cooperative allosteric regulation and a unique oligomerization. We also report structures of the enzyme in complex with ATP and ADP-glucose. Communication between the regulator-binding sites and the active site is both subtle and complex and involves several distinct regions of the enzyme including the N-terminus, the glucose-1-phosphate-binding site, and the ATP-binding site. These structures provide insights into the mechanism for catalysis and allosteric regulation of the enzyme.

  • Keywords:

    • ADP-glucose,
    • pyrophosphorylase,
    • starch biosynthesis