Mechanism-based Inhibition Reveals Transitions between Two Conformational States in the Action of Lysine 5,6-Aminomutase: A Combination of Electron Paramagnetic Resonance Spectroscopy, Electron Nuclear Double Resonance Spectroscopy, and Density Functional Theory Study
An "open"-state crystal structure of lysine 5,6-aminomutase suggests that transition to a hypothetical "closed"-state is required to bring the cofactors adenosylcobalamin (AdoCbl) and pyridoxal-5′-phosphate (PLP) and the substrate into proximity for the radical-mediated 1,2-amino group migration. Th...
| Publicado en: | Journal of the American Chemical Society Vol. 135; no. 2; pp. 788 - 795 |
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| Autores principales: | , , , |
| Formato: | Artículo |
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American Chemical Society
1/16/2013
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=85422764&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 85422764 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 1/16/2013 vid: 135 iid: 2 pid: 997 pub: American Chemical Society artinfo: ui: 85422764 10.1021/ja309603a ppf: 788 ppct: 7 formats: tig: atl: Mechanism-based Inhibition Reveals Transitions between Two Conformational States in the Action of Lysine 5,6-Aminomutase: A Combination of Electron Paramagnetic Resonance Spectroscopy, Electron Nuclear Double Resonance Spectroscopy, and Density Functional Theory Study aug: au: Yung-Han Chen Maity, Amarendra N. Frey, Perry A. Shyue-Chu Ke affil: Physics Department, National Dong Hwa University, Hualien, Taiwan 97401 Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53726, United States su: Lysine Electron paramagnetic resonance spectroscopy Electron nuclear double resonance spectroscopy Density functionals Conformational analysis sug: subj: Lysine Electron paramagnetic resonance spectroscopy Electron nuclear double resonance spectroscopy Density functionals Conformational analysis ab: An "open"-state crystal structure of lysine 5,6-aminomutase suggests that transition to a hypothetical "closed"-state is required to bring the cofactors adenosylcobalamin (AdoCbl) and pyridoxal-5′-phosphate (PLP) and the substrate into proximity for the radical-mediated 1,2-amino group migration. This process is achieved by transaldimination of the PLP-Lys144β internal aldimine with the PLP-substrate external aldimine. A closed-state crystal structure is not available. UV-vis and electron paramagnetic resonance studies show that homologues of substrate d-lysine, 2,5-DAPn, 2,4-DAB, and 2,3-DAPr bind to PLP as an external aldimine and elicit the AdoCbl Co-C bond homolysis and the accumulations of cob(II)alamin and analogue-based radicals, demonstrating the existence of a closed state. H- and P-electron nuclear double resonance studies, supported by computations, show that the position for hydrogen atom abstraction from 2,5-DAPn and 2,4-DAB by the 5′-deoxyadenosyl radical occurs at the carbon adjacent to the imine, resulting in overstabilized radicals by spin delocalization through the imine into the pyridine ring of PLP. These radicals block the active site, inhibit the enzyme, and poise the enzyme into two distinct conformations: for even-numbered analogues, the cob(II)alamin remains proximal to and spin-coupled with the analogue-based radical in the closed state while odd-numbered analogues could trigger the transition to the open state of the enzyme. We provide here direct spectroscopic evidence that strongly support the existence of a closed state and its analogue-dependent transition to the open state, which is one step that was proposed to complete the catalytic turnover of the substrate lysine. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2013 holdings: @attributes: islocal: N |
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