Structure of Escherichia coli ribose-5-phosphate isomerase: a ubiquitous enzyme of the pentose phosphate pathway and the Calvin cycle

Structure. 2003 Jan;11(1):31-42. doi: 10.1016/s0969-2126(02)00933-4.

Abstract

Ribose-5-phosphate isomerase A (RpiA; EC 5.3.1.6) interconverts ribose-5-phosphate and ribulose-5-phosphate. This enzyme plays essential roles in carbohydrate anabolism and catabolism; it is ubiquitous and highly conserved. The structure of RpiA from Escherichia coli was solved by multiwavelength anomalous diffraction (MAD) phasing, and refined to 1.5 A resolution (R factor 22.4%, R(free) 23.7%). RpiA exhibits an alpha/beta/(alpha/beta)/beta/alpha fold, some portions of which are similar to proteins of the alcohol dehydrogenase family. The two subunits of the dimer in the asymmetric unit have different conformations, representing the opening/closing of a cleft. Active site residues were identified in the cleft using sequence conservation, as well as the structure of a complex with the inhibitor arabinose-5-phosphate at 1.25 A resolution. A mechanism for acid-base catalysis is proposed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aldose-Ketose Isomerases / chemistry*
  • Aldose-Ketose Isomerases / genetics
  • Aldose-Ketose Isomerases / metabolism
  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Crystallography, X-Ray
  • Dimerization
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / metabolism
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Structure
  • Pentose Phosphate Pathway*
  • Protein Structure, Tertiary*
  • Sequence Alignment

Substances

  • Enzyme Inhibitors
  • Escherichia coli Proteins
  • glucosamine-6-phosphate isomerase
  • Aldose-Ketose Isomerases
  • ribosephosphate isomerase

Associated data

  • PDB/1KS2
  • PDB/1O8B