These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Mono- and bis-phosphine-ligated H93G myoglobin: spectral models for ferrous-phosphine and ferrous-CO cytochrome P450.
    Author: Sun S, Sono M, Dawson JH.
    Journal: J Inorg Biochem; 2013 Oct; 127():238-45. PubMed ID: 23639797.
    Abstract:
    To further investigate the properties of phosphines as structural and functional probes of heme proteins, mono- and bis-phosphine [tris(hydroxymethyl)phosphine, THMP] adducts of H93G myoglobin (Mb) have been prepared by stepwise THMP titrations of exogenous ligand-free ferric and ferrous H93G Mb, respectively. Bubbling with CO or stepwise titration with imidazole (Im) of the bis-THMP-ligated ferrous protein generated a mixed ligand (THMP/CO or THMP/Im, respectively) ferrous complexes. Stable oxyferrous H93G(THMP) Mb was formed at -40°C by bubbling the mono-THMP-Fe(II) protein with O2. A THMP-ligated ferryl H93G Mb moiety has been partially formed upon addition of H2O2 to the ferric mono-THMP adduct. All the species prepared above have been characterized with UV-visible (UV-vis) absorption and magnetic circular dichroism (MCD) spectroscopy in this study. The six-coordinate ferrous bis-phosphine and mono-phosphine/CO complexes of H93G Mb exhibit characteristic spectral features (red-shifted Soret/unique-shaped MCD visible bands and hyperporphyrin spectra, respectively) that only have been seen for the analogous phosphine or CO-complexes of thiolate-ligated heme proteins such as cytochrome P450 (P450) and Caldariomyces fumago chloroperoxidase (CPO). However, such resemblance is not seen in phosphine-ligated ferric H93G Mb even though phosphine-bound ferric P450 and CPO display hyperporphyrin spectra. In fact, bis-THMP-bound ferric H93G Mb exhibits MCD and UV-vis absorption spectra that are similar to those of bis-amine- and bis-thioether-ligated H93G Mb complexes. This study also further demonstrates the utility of the H93G cavity mutant for preparing novel heme iron coordination structures.
    [Abstract] [Full Text] [Related] [New Search]