title: Spectroscopic analysis of protein Fe-NO complexes.
abstract: The toxic free radical NO (nitric oxide) has diverse biological roles in eukaryotes and bacteria, being involved in signalling, vasodilation, blood clotting and immunity, and as an intermediate in microbial denitrification. The predominant biological mechanism of detecting NO is through the formation of iron nitrosyl complexes, although this is a deleterious process for other iron-containing enzymes. We have previously applied techniques such as UV-visible and EPR spectroscopy to the analysis of protein Fe-NO complex formation in order to study how NO controls the activity of the bacterial transcriptional regulators NorR and NsrR. These studies have analysed NO-dependent biological activity both in vitro and in vivo using diverse biochemical, molecular and spectroscopic methods. Recently, we have applied ultrafast 2D-IR (two-dimensional IR) spectroscopy to the analysis of NO-protein interactions using Mb (myoglobin) and Cc (cytochrome c) as model haem proteins. The ultrafast fluctuations of Cc and Mb show marked differences, indicating altered flexibility of the haem pockets. We have extended this analysis to bacterial catalase enzymes that are known to play a role in the nitrosative stress response by detoxifying peroxynitrite. The first 2D-IR analysis of haem nitrosylation and perspectives for the future are discussed.
authors.affiliation: Strathclyde Institute for Pharmaceutical and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 ORE, UK.
authors.forename: César
authors.initials: C
authors.lastname: Bellota-Antón
authors.forename: John
authors.initials: J
authors.lastname: Munnoch
authors.forename: Kirsty
authors.initials: K
authors.lastname: Robb
authors.forename: Katrin
authors.initials: K
authors.lastname: Adamczyk
authors.forename: Marco
authors.initials: M
authors.lastname: Candelaresi
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Parker
authors.forename: Ray
authors.initials: R
authors.lastname: Dixon
authors.forename: Matthew I
authors.initials: MI
authors.lastname: Hutchings
authors.forename: Neil T
authors.initials: NT
authors.lastname: Hunt
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Tucker
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D045304:Cytochromes c / Q000737:chemistry / Q000378:metabolism; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D009211:Myoglobin / Q000737:chemistry / Q000378:metabolism; D009569:Nitric Oxide / Q000737:chemistry* / Q000378:metabolism; D013057:Spectrum Analysis / Q000295:instrumentation / Q000379:methods*; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D009211:Myoglobin; D015534:Trans-Activators; D009569:Nitric Oxide; D006418:Heme; D045304:Cytochromes c; D007501:Iron