Magnetic and spectroscopic characterization of the high-spin (6A1) .dblharw. low-spin (2T2) transition in an iron(III) complex of pyridoxal thiosemicarbazone

1989 ◽  
Vol 28 (1) ◽  
pp. 96-99 ◽  
Author(s):  
Madan Mohan ◽  
Puranam H. Madhuranath ◽  
Alok Kumar ◽  
Munesh Kumar ◽  
Narendra K. Jha
Keyword(s):  
High Spin ◽  
Spectroscopic Characterization

Synthetic, Structural, and Spectroscopic Characterization of a Novel Family of High-Spin Iron(II) [(β-Diketiminate)(phosphanylphosphido)] Complexes

2017 ◽  
Vol 56 (18) ◽  
pp. 11030-11042 ◽  
Author(s):  
Rafał Grubba ◽  
Kinga Kaniewska ◽  
Łukasz Ponikiewski ◽  
Beata Cristóvão ◽  
Wiesława Ferenc ◽  
...  
Keyword(s):  
High Spin ◽  
Spectroscopic Characterization ◽  
High Spin Iron

scholarly journals Synthesis and Spectroscopic Characterization of High-Spin Mononuclear Iron(II) p-Semiquinonate Complexes

2014 ◽  
Vol 53 (23) ◽  
pp. 12240-12242 ◽  
Author(s):  
Amanda E. Baum ◽  
Heaweon Park ◽  
Sergey V. Lindeman ◽  
Adam T. Fiedler
Keyword(s):  
High Spin ◽  
Spectroscopic Characterization ◽  
Mononuclear Iron

scholarly journals Structural and Spectroscopic Characterization of a High-Spin {FeNO}6 Complex with an Iron(IV)−NO− Electronic Structure

2016 ◽  
Vol 128 (23) ◽  
pp. 6797-6800 ◽  
Author(s):  
Amy L. Speelman ◽  
Bo Zhang ◽  
Carsten Krebs ◽  
Nicolai Lehnert
Keyword(s):  
Electronic Structure ◽  
High Spin ◽  
Spectroscopic Characterization

scholarly journals A functional description of CymA, an electron-transfer hub supporting anaerobic respiratory flexibility in Shewanella

2012 ◽  
Vol 444 (3) ◽  
pp. 465-474 ◽  
Author(s):  
Sophie J. Marritt ◽  
Thomas G. Lowe ◽  
Jordan Bye ◽  
Duncan G. G. McMillan ◽  
Liang Shi ◽  
...  
Keyword(s):  
High Spin ◽  
Shewanella Oneidensis ◽  
Spectroscopic Characterization ◽  
Spectroscopic Studies ◽  
Redox Partner ◽  
Quinol Oxidation ◽  
Thermodynamic Driving Force ◽  
Redox Poise ◽  
Quinol Binding

CymA (tetrahaem cytochrome c) is a member of the NapC/NirT family of quinol dehydrogenases. Essential for the anaerobic respiratory flexibility of shewanellae, CymA transfers electrons from menaquinol to various dedicated systems for the reduction of terminal electron acceptors including fumarate and insoluble minerals of Fe(III). Spectroscopic characterization of CymA from Shewanella oneidensis strain MR-1 identifies three low-spin His/His co-ordinated c-haems and a single high-spin c-haem with His/H2O co-ordination lying adjacent to the quinol-binding site. At pH 7, binding of the menaquinol analogue, 2-heptyl-4-hydroxyquinoline-N-oxide, does not alter the mid-point potentials of the high-spin (approximately −240 mV) and low-spin (approximately −110, −190 and −265 mV) haems that appear biased to transfer electrons from the high- to low-spin centres following quinol oxidation. CymA is reduced with menadiol (Em=−80 mV) in the presence of NADH (Em=−320 mV) and an NADH–menadione (2-methyl-1,4-naphthoquinone) oxidoreductase, but not by menadiol alone. In cytoplasmic membranes reduction of CymA may then require the thermodynamic driving force from NADH, formate or H2 oxidation as the redox poise of the menaquinol pool in isolation is insufficient. Spectroscopic studies suggest that CymA requires a non-haem co-factor for quinol oxidation and that the reduced enzyme forms a 1:1 complex with its redox partner Fcc3 (flavocytochrome c3 fumarate reductase). The implications for CymA supporting the respiratory flexibility of shewanellae are discussed.

Sign in / Sign up

Export Citation Format

Share Document