TY - JOUR
T1 - Crystal structures of mutant IspH proteins reveal a rotation of the substrate's hydroxymethyl group during catalysis
AU - Span, Ingrid
AU - Gräwert, Tobias
AU - Bacher, Adelbert
AU - Eisenreich, Wolfgang
AU - Groll, Michael
N1 - Funding Information:
We are very grateful to Dr. Eric Oldfield and to Dr. Jörg Eppinger for their valuable feedback and discussions on the manuscript. The staffs of the X06SA beamline at the Paul Scherer Institute, Swiss Light Source, in particular Takashi Tomizaki, are thankfully acknowledged for help during data collection. This work was supported by the TUM Graduate School , the Hans-Fischer Gesellschaft and Deutsche Forschungsgemeinschaft grant GR1861/5-1 .
PY - 2012/2/10
Y1 - 2012/2/10
N2 - Isoprenoids derive from two universal precursors, isopentenyl diphosphate and dimethylallyl diphosphate, which in most human pathogens are synthesized in the deoxyxylulose phosphate pathway. The last step of this pathway is the conversion of (E)-1-hydroxy-2-methylbut-2-enyl-4-diphosphate into a mixture of isopentenyl diphosphate and dimethylallyl diphosphate catalyzed by the iron-sulfur protein IspH. The crystal structures reported here of the IspH mutant proteins T167C, E126D and E126Q reveal an alternative substrate conformation compared to the wild-type structure. Thus, the previously observed alkoxide complex decomposes, and the substrate's hydroxymethyl group rotates to interact with Glu126. The carboxyl group of Glu126 then donates a proton to the hydroxyl group to enable water elimination. The structural and functional studies provide further knowledge of the IspH reaction mechanism, which opens up new routes to inhibitor design against malaria and tuberculosis.
AB - Isoprenoids derive from two universal precursors, isopentenyl diphosphate and dimethylallyl diphosphate, which in most human pathogens are synthesized in the deoxyxylulose phosphate pathway. The last step of this pathway is the conversion of (E)-1-hydroxy-2-methylbut-2-enyl-4-diphosphate into a mixture of isopentenyl diphosphate and dimethylallyl diphosphate catalyzed by the iron-sulfur protein IspH. The crystal structures reported here of the IspH mutant proteins T167C, E126D and E126Q reveal an alternative substrate conformation compared to the wild-type structure. Thus, the previously observed alkoxide complex decomposes, and the substrate's hydroxymethyl group rotates to interact with Glu126. The carboxyl group of Glu126 then donates a proton to the hydroxyl group to enable water elimination. The structural and functional studies provide further knowledge of the IspH reaction mechanism, which opens up new routes to inhibitor design against malaria and tuberculosis.
KW - IspH
KW - LytB
KW - iron-sulfur protein
KW - isoprenoid biosynthesis
KW - non-mevalonate pathway
UR - http://www.scopus.com/inward/record.url?scp=84856491375&partnerID=8YFLogxK
U2 - 10.1016/j.jmb.2011.11.033
DO - 10.1016/j.jmb.2011.11.033
M3 - Article
C2 - 22137895
AN - SCOPUS:84856491375
SN - 0022-2836
VL - 416
SP - 1
EP - 9
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 1
ER -