Twists and turns: a tale of two shikimate-pathway enzymes.
We are studying two enzymes from the shikimate pathway, dehydroquinate synthase (DHQS) and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Both enzymes have been the subject of numerous studies to elucidate their reaction mechanisms. Crystal structures of DHQS and EPSPS in the presence and absence of substrates, cofactors and/or inhibitors are now available. These structures reveal movements of domains, rearrangements of loops and changes in side-chain positions necessary for the formation of a catalytically competent active site. The potential for using complementary small-angle X-ray scattering (SAXS) studies to confirm the presence of these structural differences in solution has also been explored. Comparative analysis of crystal structures, in the presence and absence of ligands, has revealed structural features critical for substrate-binding and catalysis. We have also analysed these structures by generating GRID energy maps to detect favourable binding sites. The combination of X-ray crystallography, SAXS and computational techniques provides an enhanced analysis of structural features important for the function of these complex enzymes.
Brown
K A
KA
Department of Biological Sciences, CMMI, Flowers Building, Imperial College, London SW7 2AY, UK. k.brown@ic.ac.uk
Carpenter
E P
EP
Watson
K A
KA
Coggins
J R
JR
Hawkins
A R
AR
Koch
M H J
MH
Svergun
D I
DI
D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D008958:Models, Molecular; D019761:Phosphorus-Oxygen Lyases / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D012765:Shikimic Acid / Q000378:metabolism*; D014961:X-Ray Diffraction
D012765:Shikimic Acid; D019883:Alkyl and Aryl Transferases; D051229:3-Phosphoshikimate 1-Carboxyvinyltransferase; C020001:3-dehydroquinate synthetase; D019761:Phosphorus-Oxygen Lyases