Abstract |
Nm23-H1/NDPK-A, a tumour metastasis suppressor, is a multifunctional housekeeping enzyme with nucleoside diphosphate kinase activity. Hexameric Nm23-H1 is required for suppression of tumour metastasis and it is dissociated into dimers under oxidative conditions. Here, the crystal structure of oxidized Nm23-H1 is presented. It reveals the formation of an intramolecular disulfide bond between Cys4 and Cys145 that triggers a large conformational change that destabilizes the hexameric state. The dependence of the dissociation dynamics on the H2O2 concentration was determined using hydrogen/ deuterium-exchange experiments. The quaternary conformational change provides a suitable environment for the oxidation of Cys109 to sulfonic acid, as demonstrated by peptide sequencing using nanoUPLC-ESI-q-TOF tandem MS. From these and other data, it is proposed that the molecular and cellular functions of Nm23-H1 are regulated by a series of oxidative modifications coupled to its oligomeric states and that the modified cysteines are resolvable by NADPH-dependent reduction systems. These findings broaden the understanding of the complicated enzyme-regulatory mechanisms that operate under oxidative conditions.
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Authors | Mi-Sun Kim, Jaeho Jeong, Jihye Jeong, Dong-Hae Shin, Kong-Joo Lee |
Journal | Acta crystallographica. Section D, Biological crystallography
(Acta Crystallogr D Biol Crystallogr)
Vol. 69
Issue Pt 4
Pg. 669-80
(Apr 2013)
ISSN: 1399-0047 [Electronic] United States |
PMID | 23519676
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Cross-Linking Reagents
- Disulfides
- NM23 Nucleoside Diphosphate Kinases
- NME1 protein, human
- Cysteine
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Topics |
- Amino Acid Sequence
- Cross-Linking Reagents
(chemistry)
- Crystallography, X-Ray
- Cysteine
(chemistry, genetics)
- Disulfides
(chemistry)
- Humans
- Molecular Dynamics Simulation
- Molecular Sequence Data
- Mutation
- NM23 Nucleoside Diphosphate Kinases
(chemistry, genetics)
- Oxidative Stress
(genetics)
- Protein Conformation
- Protein Stability
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