- Biomimetic Design Results in a Potent Allosteric Inhibitor of Dihydrodipicolinate Synthase from Campylobacter jejuni
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Dihydrodipicolinate synthase (DHDPS), an enzyme required for bacterial peptidoglycan biosynthesis, catalyzes the condensation of pyruvate and β-aspartate semialdehyde (ASA) to form a cyclic product which dehydrates to form dihydrodipicolinate. DHDPS has, for several years, been considered a putative target for novel antibiotics. We have designed the first potent inhibitor of this enzyme by mimicking its natural allosteric regulation by lysine, and obtained a crystal structure of the protein-inhibitor complex at 2.2 ? resolution. This novel inhibitor, which we named 'bislysine', resembles two lysine molecules linked by an ethylene bridge between the α-carbon atoms. Bislysine is a mixed partial inhibitor with respect to the first substrate, pyruvate, and a noncompetitive partial inhibitor with respect to ASA, and binds to all forms of the enzyme with a Ki near 200 nM, more than 300 times more tightly than lysine. Hill plots show that the inhibition is cooperative, indicating that the allosteric sites are not independent despite being located on opposite sides of the protein tetramer, separated by approximately 50 ?. A mutant enzyme resistant to lysine inhibition, Y110F, is strongly inhibited by this novel inhibitor, suggesting this may be a promising strategy for antibiotic development.
- Skovpen, Yulia V.,Conly, Cuylar J. T.,Sanders, David A. R.,Palmer, David R. J.
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supporting information
p. 2014 - 2020
(2016/03/01)
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- Synthesis of stereoisomers of 2,4-diaminoglutaric and 2,5-diaminoadipic acids
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Stereoisomers of 2,4-diaminoglutaric and 2,5-diaminoadipic acids were synthesized from glutamic and 2-aminoadipic acids, respectively.The stereochemistry of the products was established by 1H NMR spectroscopy and X-ray analysis. - Keywords: 2,4-diaminoglutaric acid; 2,5-diaminoadipic acid; nucleophilic substitution; stereoisomers; racemization
- Krasnov, V. P.,Zhdanova, E. A.,Korolyova, M. A.,Bukrina, I. M.,Kodess, M. I.,et al.
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p. 319 - 323
(2007/10/03)
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- Lithiation of Bridgehead Position in 3,6-Bridged Piperazine-2,5-diones
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2,5-Dimethyl-2,5-diazabicyclooctane-3,6-dione can be lithiated at the 1,4 (bridgehead) positions with 2 equiv. of butyllithium at -78 deg C and deuterated with D2O (D0, 11.2; D1, 56.1; D2, 30.1percent).With butyllithium and methyl iodide the 1,2,5-trimethyl and 1,2,4,5-tetramethyl derivatives are obtained.Treatment of dimethyl 2,6-diaminoheptanedioate dihydrochloride with sodium methoxide in boiling butanol gives 6,8-diazabicyclononane-7,9-dione in 62percent yield.N-Methylation of this compound yields 6,8-dimethyl-6,8-diazabicyclononane-7,9-dione which can similarly be lithiated at the 1,5 (bridgehead) positions and deuterated with D2O (D0, 5.6; D1, 70.8; D2, 23.6percent).Lithiation with butyllithium and reaction with methyl iodide, benzyl iodide or bromomethyl methyl ether gives mono- and di-alkylated products at the 1,5-position.The ability to lithiate the bridgehead positions in these compounds is attributed primarily to a combination of the inductive effect of the carbonyl group and dipole stabilization by the amide nitrogen.
- Eastwood, Frank W.,Gunawardana, Dionne,Wernert, Gregory T.
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p. 2289 - 2298
(2007/10/02)
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- Antifilarial agents. Diazabicyclooctanes and diazabicycloheptanes as bridged analogs of diethylcarbamazine
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Twelve analogs of diethylcarbamazine (DEC) were prepared by acylation of 3 and 8 methyl 3,8 diazabicyclo[3.2.1]octane, 2 methyl 2,5 diazabicyclo[2.2.2]octane, and 2 methyl 2,5 diazabicyclo[2.2.1]heptane with diethylcarbamyl chloride, ethyl chloroformate, ethyl isocyanate, and cyclohexanecarbonyl chloride. These compounds are formally derived from DEC in possessing two or one carbon bridges over the piperazine ring. When evaluated against Litomosoides carinii in the gerbil, all compounds strongly suppressed blood microfilaremia levels but did not affect the adult worms. Several compounds were nearly equivalent to DEC in activity. The results are discussed in terms of molecular model studies and receptor site theory.
- Sturm,Henry,Thompson,et al.
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p. 481 - 487
(2007/10/04)
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