TY - JOUR
T1 - The inosine monophosphate dehydrogenase, GuaB2, is a vulnerable new bactericidal drug target for tuberculosis
AU - Singh, Vinayak
AU - Donini, Stefano
AU - Pacitto, Angela
AU - Sala, Claudia
AU - Hartkoorn, Ruben C.
AU - Dhar, Neeraj
AU - Keri, Gyorgy
AU - Ascher, David B.
AU - Mondésert, Guillaume
AU - Vocat, Anthony
AU - Lupien, Andréanne
AU - Sommer, Raphael
AU - Vermet, Hélène
AU - Lagrange, Sophie
AU - Buechler, Joe
AU - Warner, Digby F.
AU - McKinney, John D.
AU - Pato, Janos
AU - Cole, Stewart T.
AU - Blundell, Tom L.
AU - Rizzi, Menico
AU - Mizrahi, Valerie
N1 - Funding Information:
This work was funded by the European Community’s Seventh Framework Programme (Grant 260872); the South African Medical Research Council (to V.M.); the National Research Foundation of South Africa (to V.M.); a Senior International Research Scholar’s grant from the HHMI (Grant 55007649 to V.M.); the Bill and Melinda Gates Foundation (to A.P. and T.L.B.), a Newton Fund RCUK-CONFAP grant awarded by The Medical Research Council (MRC) and Fundaca̧ õ de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) (Grant MR/M026302/1 to T.L.B. and D.B.A.), a NHMRC CJ Martin Fellowship (Grant APP1072476 to D.B.A.); the Swiss National Science Foundation (31003A-162641) and the Fondation Beytout (to S.T.C.); the University of Cambridge and The Wellcome Trust for facilities and support (to T.L.B.).
PY - 2017/1/13
Y1 - 2017/1/13
N2 - VCC234718, a molecule with growth inhibitory activity against Mycobacterium tuberculosis (Mtb), was identified by phenotypic screening of a 15344-compound library. Sequencing of a VCC234718-resistant mutant identified a Y487C substitution in the inosine monophosphate dehydrogenase, GuaB2, which was subsequently validated to be the primary molecular target of VCC234718 in Mtb. VCC234718 inhibits Mtb GuaB2 with a Ki of 100 nM and is uncompetitive with respect to IMP and NAD+. This compound binds at the NAD+ site, after IMP has bound, and makes direct interactions with IMP; therefore, the inhibitor is by definition uncompetitive. VCC234718 forms strong pi interactions with the Y487 residue side chain from the adjacent protomer in the tetramer, explaining the resistance-conferring mutation. In addition to sensitizing Mtb to VCC234718, depletion of GuaB2 was bactericidal in Mtb in vitro and in macrophages. When supplied at a high concentration (≥125 μM), guanine alleviated the toxicity of VCC234718 treatment or GuaB2 depletion via purine salvage. However, transcriptional silencing of guaB2 prevented Mtb from establishing an infection in mice, confirming that Mtb has limited access to guanine in this animal model. Together, these data provide compelling validation of GuaB2 as a new tuberculosis drug target.
AB - VCC234718, a molecule with growth inhibitory activity against Mycobacterium tuberculosis (Mtb), was identified by phenotypic screening of a 15344-compound library. Sequencing of a VCC234718-resistant mutant identified a Y487C substitution in the inosine monophosphate dehydrogenase, GuaB2, which was subsequently validated to be the primary molecular target of VCC234718 in Mtb. VCC234718 inhibits Mtb GuaB2 with a Ki of 100 nM and is uncompetitive with respect to IMP and NAD+. This compound binds at the NAD+ site, after IMP has bound, and makes direct interactions with IMP; therefore, the inhibitor is by definition uncompetitive. VCC234718 forms strong pi interactions with the Y487 residue side chain from the adjacent protomer in the tetramer, explaining the resistance-conferring mutation. In addition to sensitizing Mtb to VCC234718, depletion of GuaB2 was bactericidal in Mtb in vitro and in macrophages. When supplied at a high concentration (≥125 μM), guanine alleviated the toxicity of VCC234718 treatment or GuaB2 depletion via purine salvage. However, transcriptional silencing of guaB2 prevented Mtb from establishing an infection in mice, confirming that Mtb has limited access to guanine in this animal model. Together, these data provide compelling validation of GuaB2 as a new tuberculosis drug target.
UR - https://www.scopus.com/pages/publications/85018519349
U2 - 10.1021/acsinfecdis.6b00102
DO - 10.1021/acsinfecdis.6b00102
M3 - Article
SN - 2373-8227
VL - 3
SP - 5
EP - 17
JO - ACS Infectious Diseases
JF - ACS Infectious Diseases
IS - 1
ER -
SDG 3 Salute e benessere