The three-dimensional structure of shikimate kinase.
The three-dimensional structure of shikimate kinase from Erwinia chrysanthemi has been determined by multiple isomorphous replacement. Two models are presented: a high resolution 1.9 A model and a 2.6 A model which contains bound Mg-ADP. The enzyme is an alpha/beta protein consisting of a central sheet of five parallel beta-strands flanked by alpha-helices with overall topology similar to adenylate kinase. Evidence is presented that shikimate kinase undergoes major conformational changes on ligand binding. It resembles adenylate kinase in having a P-loop containing core structure and two flexible domains which undergo induced fit movement on substrate binding. The binding of Mg2+ in the active site of shikimate kinase involves direct interaction with two protein side-chains which is different from the situation found in adenylate kinase. Shikimate kinase has a readily identifiable Walker A-motif and a recognisable but modified Walker B-motif. Comparison of shikimate kinase to adenylate kinase has led to the identification of an adenine-binding motif (I/VDAXQ/NXP). Difference Fourier calculations have revealed the shikimate binding site which corresponds to the location of the AMP-binding site in adenylate kinase. A model for shikimate-binding is presented.
Krell
T
T
Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
Coggins
J R
JR
Lapthorn
A J
AJ
D000244:Adenosine Diphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D016974:Dickeya chrysanthemi / Q000201:enzymology*; D006801:Humans; D008024:Ligands; D008274:Magnesium / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D008024:Ligands; D000244:Adenosine Diphosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); C022642:shikimate kinase; D008274:Magnesium