1
|
Kim HT, Na BK, Chung J, Kim S, Kwon SK, Cha H, Son J, Cho JM, Hwang KY. Structural Basis for Inhibitor-Induced Hydrogen Peroxide Production by Kynurenine 3-Monooxygenase. Cell Chem Biol 2018; 25:426-438.e4. [PMID: 29429898 DOI: 10.1016/j.chembiol.2018.01.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 10/17/2017] [Accepted: 01/08/2018] [Indexed: 11/18/2022]
Abstract
Kynurenine 3-monooxygenase (KMO) inhibitors have been developed for the treatment of neurodegenerative disorders. The mechanisms of flavin reduction and hydrogen peroxide production by KMO inhibitors are unknown. Herein, we report the structure of human KMO and crystal structures of Saccharomyces cerevisiae (sc) and Pseudomonas fluorescens (pf) KMO with Ro 61-8048. Proton transfer in the hydrogen bond network triggers flavin reduction in p-hydroxybenzoate hydroxylase, but the mechanism triggering flavin reduction in KMO is different. Conformational changes via π-π interactions between the loop above the flavin and substrate or non-substrate effectors lead to disorder of the C-terminal α helix in scKMO and shifts of domain III in pfKMO, stimulating flavin reduction. Interestingly, Ro 61-8048 has two different binding modes. It acts as a competitive inhibitor in scKMO and as a non-substrate effector in pfKMO. These findings provide understanding of the catalytic cycle of KMO and insight for structure-based drug design of KMO inhibitors.
Collapse
Affiliation(s)
- Hyun Tae Kim
- Crystalgenomics, Inc., 5F, Tower A, Korea Bio Park 700, Daewangpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 13524, Korea; Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea
| | - Byeong Kwan Na
- Crystalgenomics, Inc., 5F, Tower A, Korea Bio Park 700, Daewangpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 13524, Korea
| | - Jiwoung Chung
- Crystalgenomics, Inc., 5F, Tower A, Korea Bio Park 700, Daewangpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 13524, Korea
| | - Sulhee Kim
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea
| | - Sool Ki Kwon
- Crystalgenomics, Inc., 5F, Tower A, Korea Bio Park 700, Daewangpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 13524, Korea
| | - Hyunju Cha
- Crystalgenomics, Inc., 5F, Tower A, Korea Bio Park 700, Daewangpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 13524, Korea
| | - Jonghyeon Son
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea
| | - Joong Myung Cho
- Crystalgenomics, Inc., 5F, Tower A, Korea Bio Park 700, Daewangpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 13524, Korea.
| | - Kwang Yeon Hwang
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Korea.
| |
Collapse
|
2
|
Haque MM, Fadlalla MA, Aulak KS, Ghosh A, Durra D, Stuehr DJ. Control of electron transfer and catalysis in neuronal nitric-oxide synthase (nNOS) by a hinge connecting its FMN and FAD-NADPH domains. J Biol Chem 2012; 287:30105-16. [PMID: 22722929 PMCID: PMC3436266 DOI: 10.1074/jbc.m112.339697] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 06/13/2012] [Indexed: 01/19/2023] Open
Abstract
In nitric-oxide synthases (NOSs), two flexible hinges connect the FMN domain to the rest of the enzyme and may guide its interactions with partner domains for electron transfer and catalysis. We investigated the role of the FMN-FAD/NADPH hinge in rat neuronal NOS (nNOS) by constructing mutants that either shortened or lengthened this hinge by 2, 4, and 6 residues. Shortening the hinge progressively inhibited electron flux through the calmodulin (CaM)-free and CaM-bound nNOS to cytochrome c, whereas hinge lengthening relieved repression of electron flux in CaM-free nNOS and had no impact or slowed electron flux through CaM-bound nNOS to cytochrome c. How hinge length influenced heme reduction depended on whether enzyme flavins were pre-reduced with NADPH prior to triggering heme reduction. Without pre-reduction, changing the hinge length was deleterious; with pre-reduction, the hinge shortening was deleterious, and hinge lengthening increased heme reduction rates beyond wild type. Flavin fluorescence and stopped-flow kinetic studies on CaM-bound enzymes suggested hinge lengthening slowed the domain-domain interaction needed for FMN reduction. All hinge length changes lowered NO synthesis activity and increased uncoupled NADPH consumption. We conclude that several aspects of catalysis are sensitive to FMN-FAD/NADPH hinge length and that the native hinge allows a best compromise among the FMN domain interactions and associated electron transfer events to maximize NO synthesis and minimize uncoupled NADPH consumption.
Collapse
Affiliation(s)
- Mohammad Mahfuzul Haque
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Mohammed A. Fadlalla
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Kulwant S. Aulak
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Arnab Ghosh
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Deborah Durra
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Dennis J. Stuehr
- From the Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| |
Collapse
|