TY - JOUR
T1 - Metabolically distinct roles of NAD synthetase and NAD kinase definethe essentiality of NAD and NADP in Mycobacterium tuberculosis
AU - Sharma, Ritu
AU - Hartman, Travis E.
AU - Beites, Tiago
AU - Kim, Jee Hyun
AU - Eoh, Hyungjin
AU - Engelhart, Curtis A.
AU - Zhu, Linnan
AU - Wilson, Daniel J.
AU - Aldrich, Courtney C.
AU - Ehrt, Sabine
AU - Rhee, Kyu Young
AU - Schnappinger, Dirk
N1 - Publisher Copyright:
© 2023 Sharma et al.
PY - 2023/7
Y1 - 2023/7
N2 - Nicotinamide adenine dinucleotide (NAD) and its phosphorylated derivative (NADP) are essential cofactors that participate in hundreds of biochemical reactions and have emerged as therapeutic targets in cancer, metabolic disorders, neurodegenerative diseases, and infections, including tuberculosis. The biological basis for the essentiality of NAD(P) in most settings, however, remains experimentally unexplained. Here, we report that inactivation of the terminal enzyme of NAD synthesis, NAD synthetase (NadE), elicits markedly differentmetabolic and microbiologic effectsthan those of the terminal enzyme of NADP biosynthesis, NAD kinase (PpnK), in Mycobacterium tuberculosis (Mtb). Inactivation of NadE led to parallel reductions of both NAD and NADP pools and Mtb viability, while inactivation of PpnK selectively depleted NADP pools but only arrested growth. Inactivation of each enzyme was accompanied by metabolic changes that were specificfor the affectedenzyme and associated microbiological phenotype. Bacteriostatic levels of NAD depletion caused a compensatory remodeling of NAD-dependent metabolic pathways in the absence of an impact on NADH/NAD ratios, while bactericidal levels of NAD depletion resulted in a disruption of NADH/NAD ratios and inhibition of oxygen respiration. These findingsreveal a previously unrecognized physiologic specificityassociated with the essentiality of two evolutionarily ubiquitous cofactors.
AB - Nicotinamide adenine dinucleotide (NAD) and its phosphorylated derivative (NADP) are essential cofactors that participate in hundreds of biochemical reactions and have emerged as therapeutic targets in cancer, metabolic disorders, neurodegenerative diseases, and infections, including tuberculosis. The biological basis for the essentiality of NAD(P) in most settings, however, remains experimentally unexplained. Here, we report that inactivation of the terminal enzyme of NAD synthesis, NAD synthetase (NadE), elicits markedly differentmetabolic and microbiologic effectsthan those of the terminal enzyme of NADP biosynthesis, NAD kinase (PpnK), in Mycobacterium tuberculosis (Mtb). Inactivation of NadE led to parallel reductions of both NAD and NADP pools and Mtb viability, while inactivation of PpnK selectively depleted NADP pools but only arrested growth. Inactivation of each enzyme was accompanied by metabolic changes that were specificfor the affectedenzyme and associated microbiological phenotype. Bacteriostatic levels of NAD depletion caused a compensatory remodeling of NAD-dependent metabolic pathways in the absence of an impact on NADH/NAD ratios, while bactericidal levels of NAD depletion resulted in a disruption of NADH/NAD ratios and inhibition of oxygen respiration. These findingsreveal a previously unrecognized physiologic specificityassociated with the essentiality of two evolutionarily ubiquitous cofactors.
KW - Mycobacterium tuberculosis
KW - NAD
KW - NADPH
KW - drug targets
KW - metabolism
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U2 - 10.1128/mbio.00340-23
DO - 10.1128/mbio.00340-23
M3 - Article
C2 - 37350592
AN - SCOPUS:85169501909
SN - 2161-2129
VL - 14
JO - mBio
JF - mBio
IS - 4
ER -