The structure and mechanism of the type II dehydroquinase from Streptomyces coelicolor.
The structure of the type II DHQase from Streptomyces coelicolor has been solved and refined to high resolution in complexes with a number of ligands, including dehydroshikimate and a rationally designed transition state analogue, 2,3-anhydro-quinic acid. These structures define the active site of the enzyme and the role of key amino acid residues and provide snap shots of the catalytic cycle. The resolution of the flexible lid domain (residues 21-31) shows that the invariant residues Arg23 and Tyr28 close over the active site cleft. The tyrosine acts as the base in the initial proton abstraction, and evidence is provided that the reaction proceeds via an enol intermediate. The active site of the structure of DHQase in complex with the transition state analog also includes molecules of tartrate and glycerol, which provide a basis for further inhibitor design.
Roszak
Aleksander W
AW
Department of Chemistry, Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, United Kingdom.
Robinson
David A
DA
Krell
Tino
T
Hunter
Iain S
IS
Fredrickson
Martyn
M
Abell
Chris
C
Coggins
John R
JR
Lapthorn
Adrian J
AJ
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006836:Hydro-Lyases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D012765:Shikimic Acid / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology*
D001426:Bacterial Proteins; D012765:Shikimic Acid; D006836:Hydro-Lyases; C020000:3-dehydroquinate dehydratase