Pantothenate is synthesized in bacteria, fungi and plants, and as vitamin B5 is a dietary requirement in animals. The three-dimensional structures of the four Escherichia coli enzymes involved in the production of pantothenate have been determined. We describe the use of comparative analyses of the sequences and structures to identify distant homologues of the four enzymes in an attempt to understand the evolution of the pathway. We conclude that it is likely to have evolved via a patchwork mechanism, whereby the individual enzymes were recruited separately.
- enzyme pathway
- X-ray crystallography
Enzyme Mechanism – A Structural Perspective, a Biochemical Society Focused Meeting held at St. Andrews University, 12–14 January 2003
Abbreviations used: KPHMT, ketopantoate hydroxymethyltransferase; KPR, ketopantoate reductase; ADC, aspartate decarboxylase; PS, pantothenate synthetase; PEPM, phosphoenolpyruvate mutase; ICL, isocitrate lyase; CENDH, N-(1-d-carboxyethyl)-l-norvaline dehydrogenase; AHIR, acetohydroxy isomeroreductase; G3PCT, glucose-3-phosphate cytidylyl transferase.
- © 2003 Biochemical Society