Synthesis and evaluation of substrate analogues as mechanism-based inhibitors of type II isopentenyl diphosphate isomerase.
Type 2 isopentenyl diphosphate isomerase (IDI-2), which catalyzes the interconversion of isopentenyl diphosphate and dimethylallyl diphosphate, contains a tightly bound molecule of FMN. To probe the mechanism of the reaction, cyclopropyl and epoxy substrate analogues, designed to be mechanism-based irreversible inhibitors, were synthesized and evaluated with IDI-2 from Thermus thermophilus. The cyclopropyl analogues were alternative substrates. The epoxy analogue was an irreversible inhibitor, with kI = 0.37 +/- 0.07 min(-1) and KI = 1.4 +/- 0.3 microM. LC-MS studies revealed formation of an epoxide-FMN adduct.
Walker
Joel R
JR
Department of Chemistry, University of Utah, 315 South 1400 East RM 2020, Salt Lake City, Utah 84112, USA.
Rothman
Steven C
SC
Poulter
C Dale
CD
D001665:Binding Sites / Q000187:drug effects; D019748:Carbon-Carbon Double Bond Isomerases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D003521:Cyclopropanes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D004789:Enzyme Activation / Q000187:drug effects; D004852:Epoxy Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D045782:Hemiterpenes; D015394:Molecular Structure; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D003521:Cyclopropanes; D004852:Epoxy Compounds; D045782:Hemiterpenes; D011994:Recombinant Proteins; D019748:Carbon-Carbon Double Bond Isomerases; C021453:isopentenyldiphosphate delta-isomerase