Design and Structural Analysis of Aromatic Inhibitors of Type II Dehydroquinase from Mycobacterium tuberculosis.
ChemMedChem. 2014 Sep 18;
Authors: Howard NI, Dias MV, Peyrot F, Chen L, Schmidt MF, Blundell TL, Abell C
3-Dehydroquinase, the third enzyme in the shikimate pathway, is a potential target for drugs against tuberculosis. Whilst a number of potent inhibitors of the Mycobacterium tuberculosis enzyme based on a 3-dehydroquinate core have been identified, they generally show little or no in vivo activity, and were synthetically complex to prepare. This report describes studies to develop tractable and drug-like aromatic analogues of the most potent inhibitors. A range of carbon-carbon linked biaryl analogues were prepared to investigate the effect of hydrogen bond acceptor and donor patterns on inhibition. These exhibited inhibitory activity in the high-micromolar range. The addition of flexible linkers in the compounds led to the identification of more potent 3-nitrobenzylgallate- and 5-aminoisophthalate-based analogues.
PMID: 25234229 [PubMed - as supplied by publisher]
DUET: a server for predicting effects of mutations on protein stability using an integrated computational approach.
Nucleic Acids Res. 2014 Jul;42(Web Server issue):W314-9
Authors: Pires DE, Ascher DB, Blundell TL
Cancer genome and other sequencing initiatives are generating extensive data on non-synonymous single nucleotide polymorphisms (nsSNPs) in human and other genomes. In order to understand the impacts of nsSNPs on the structure and function of the proteome, as well as to guide protein engineering, accurate in silicomethodologies are required to study and predict their effects on protein stability. Despite the diversity of available computational methods in the literature, none has proven accurate and dependable on its own under all scenarios where mutation analysis is required. Here we present DUET, a web server for an integrated computational approach to study missense mutations in proteins. DUET consolidates two complementary approaches (mCSM and SDM) in a consensus prediction, obtained by combining the results of the separate methods in an optimized predictor using Support Vector Machines (SVM). We demonstrate that the proposed method improves overall accuracy of the predictions in comparison with either method individually and performs as well as or better than similar methods. The DUET web server is freely and openly available at http://structure.bioc.cam.ac.uk/duet.
PMID: 24829462 [PubMed - indexed for MEDLINE]
Respiratory flexibility in response to inhibition of cytochrome C oxidase in Mycobacterium tuberculosis.
Antimicrob Agents Chemother. 2014 Aug 25;
Authors: Arora K, Ochoa-Montaño B, Tsang PS, Blundell TL, Dawes SS, Mizrahi V, Bayliss T, Mackenzie CJ, Cleghorn LA, Ray PC, Wyatt PG, Uh E, Lee J, Barry CE, Boshoff HI
We report here on a series of five chemically diverse scaffolds that have activity in vitro on both replicating and hypoxic non-replicating bacilli by targeting the respiratory bc1 complex in Mycobacterium tuberculosis, in a strain-dependent manner. Deletion of the cytochrome bd oxidase generated a hyper-susceptible mutant in which resistance was acquired by mutation in qcrB. These results highlight the promiscuity of the bc1 complex and highlight the risk of targeting energy metabolism with new drugs.
PMID: 25155596 [PubMed - as supplied by publisher]
Mycobacterium tuberculosis dihydrofolate reductase reveals two conformational states and a possible low affinity mechanism to antifolate drugs.
Structure. 2014 Jan 7;22(1):94-103
Authors: Dias MV, Tyrakis P, Domingues RR, Paes Leme AF, Blundell TL
Inhibition of the biosynthesis of tetrahydrofolate (THF) has long been a focus in the treatment of both cancer and infectious diseases. Dihydrofolate reductase (DHFR), which catalyzes the last step, is one of the most thoroughly explored targets of this pathway, but there are no DHFR inhibitors used for tuberculosis treatment. Here, we report a structural, site-directed mutagenesis and calorimetric analysis of Mycobacterium tuberculosis DHFR (MtDHFR) in complex with classical DHFR inhibitors. Our study provides insights into the weak inhibition of MtDHFR by trimethoprim and other antifolate drugs, such as pyrimethamine and cycloguanil. The construction of the mutant Y100F, together with calorimetric studies, gives insights into low affinity of MtDHFR for classical DHFR inhibitors. Finally, the structures of MtDHFR in complex with pyrimethamine and cycloguanil define important interactions in the active site and provide clues to the more effective design of antibiotics targeted against MtDHFR.
PMID: 24210757 [PubMed - indexed for MEDLINE]
Pantothenic acid biosynthesis in the parasite Toxoplasma gondii: a target for chemotherapy.
Antimicrob Agents Chemother. 2014 Jul 21;
Authors: Mageed SN, Cunningham F, Hung AW, Silvestre HL, Wen S, Blundell TL, Abell C, McConkey GA
Toxoplasma gondii is a major food pathogen and neglected parasitic infection that causes eye disease, birth defects, and fetal abortion and plays a role as an opportunistic infection in AIDS. In this study, we investigated pantothenic acid (vitamin B5) biosynthesis in T. gondii. Genes encoding the full repertoire of enzymes for pantothenate synthesis and subsequent metabolism to Coenzyme A were identified and are expressed in T. gondii. A panel of inhibitors developed to target Mycobacterium tuberculosis pantothenate synthetase were tested and found to exhibit a range of inhibitions of growth of T. gondii. Two inhibitors exhibited lower effective concentrations than the current toxoplasmosis drug pyrimethamine. The inhibition was specific for the pantothenate pathway as the effect of the pantothenate synthetase inhibitors was abrogated by supplementation with pantothenate. Hence, T. gondii encodes and expresses the enzymes for pantothenate synthesis and this pathway is essential for parasite growth. These promising findings increase our understanding of growth and metabolism in this important parasite and highlight pantothenate synthetase as a new drug target.
PMID: 25049241 [PubMed - as supplied by publisher]