Hough, Michael A and Antonyuk, Svetlana V and Barbieri, Sonia and Rustage, Neil and McKay, Alison L and Servid, Amy E and Eady, Robert R and Andrew, Colin R and Hasnain, S Samar (2011) Distal-to-Proximal NO Conversion in Hemoproteins: The Role of the Proximal Pocket. Journal of Molecular Biology, 405 (2). pp. 395-409. DOI https://doi.org/10.1016/j.jmb.2010.10.035
Hough, Michael A and Antonyuk, Svetlana V and Barbieri, Sonia and Rustage, Neil and McKay, Alison L and Servid, Amy E and Eady, Robert R and Andrew, Colin R and Hasnain, S Samar (2011) Distal-to-Proximal NO Conversion in Hemoproteins: The Role of the Proximal Pocket. Journal of Molecular Biology, 405 (2). pp. 395-409. DOI https://doi.org/10.1016/j.jmb.2010.10.035
Hough, Michael A and Antonyuk, Svetlana V and Barbieri, Sonia and Rustage, Neil and McKay, Alison L and Servid, Amy E and Eady, Robert R and Andrew, Colin R and Hasnain, S Samar (2011) Distal-to-Proximal NO Conversion in Hemoproteins: The Role of the Proximal Pocket. Journal of Molecular Biology, 405 (2). pp. 395-409. DOI https://doi.org/10.1016/j.jmb.2010.10.035
Abstract
Hemoproteins play central roles in the formation and utilization of nitric oxide (NO) in cellular signaling, as well as in protection against nitrosative stress. Key to heme-nitrosyl function and reactivity is the Fe coordination number (5 or 6). For (five-coordinate) 5c-NO complexes, the potential for NO to bind on either heme face exists, as in the microbial cytochrome c′ from Alcaligenes xylosoxidans (AxCYTcp), which forms a stable proximal 5c-NO complex via a distal six-coordinate NO intermediate and a putative dinitrosyl species. Strong parallels between the NO-binding kinetics of AxCYTcp, the eukaryotic NO sensor soluble guanylate cyclase, and the ferrocytochrome c/cardiolipin complex have led to the suggestion that a distal-to-proximal NO switch could contribute to the selective ligand responses in gas-sensing hemoproteins. The proximal NO-binding site in AxCYTcp is close to a conserved basic (Arg124) residue that is postulated to modulate NO reactivity. We have replaced Arg124 by five different amino acids and have determined high-resolution (1.07-1.40 Å) crystallographic structures with and without NO. These, together with kinetic and resonance Raman data, provide new insights into the mechanism of distal-to-proximal heme-NO conversion, including the determinants of Fe-His bond scission. The Arg124Ala variant allowed us to determine the structure of an analog of the previously unobserved key 5c-NO distal intermediate species. The very high resolution structures combined with the extensive spectroscopic and kinetic data have allowed us to provide a fresh insight into heme reactivity towards NO, a reaction that is of wide importance in biology. © 2010 Elsevier Ltd. All rights reserved.
Item Type: | Article |
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Uncontrolled Keywords: | NO; ligand discrimination; kinetics; resonance Raman; cytochrome |
Subjects: | Q Science > QH Natural history > QH301 Biology |
Divisions: | Faculty of Science and Health Faculty of Science and Health > Life Sciences, School of |
SWORD Depositor: | Unnamed user with email elements@essex.ac.uk |
Depositing User: | Unnamed user with email elements@essex.ac.uk |
Date Deposited: | 04 Aug 2011 15:27 |
Last Modified: | 30 Oct 2024 17:07 |
URI: | http://repository.essex.ac.uk/id/eprint/374 |