A Two-Coordinate Neutral Germylene Supported by a β-Diketiminate Ligand in the Radical State

The hypothesis of the existence of π-radical hybridization in aryl (M. Tsutsui. Ann. N.Y. Acad. Sci. 93, 133 (1961)) and vinyl (M. Tsutsui. Abstracts of Papers, 141st Meeting of the American Chemical Society, Washington, D.C. March, 1962. p. 3-O) coupling reactions has led us to a further investigation of the reactivity of highly active transition metal atoms in the so-called "radical state". As a result, a new synthetic method for bis-benzene-type π-complexes of transition metals has been discovered.

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Photoreaction of Plant and DASH Cryptochromes Probed by Infrared Spectroscopy: The Neutral Radical State of Flavoproteins

The Journal of Physical Chemistry B ◽

10.1021/jp1076388 ◽

2010 ◽

Vol 114 (51) ◽

pp. 17155-17161 ◽

Cited By ~ 24

Author(s):

Dominik Immeln ◽

Richard Pokorny ◽

Elena Herman ◽

Julia Moldt ◽

Alfred Batschauer ◽

...

Keyword(s):

Infrared Spectroscopy ◽

Neutral Radical ◽

Radical State

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Changes in the free-radical state and the level of free iron during the development of drug resistance in tumor cells

BIOPHYSICS ◽

10.1134/s0006350906030158 ◽

2006 ◽

Vol 51 (3) ◽

pp. 435-439

Author(s):

A. N. Saprin ◽

E. V. Kalinina ◽

V. A. Serezhenkov ◽

Ya. N. Kotova ◽

V. S. Solomka ◽

...

Keyword(s):

Drug Resistance ◽

Free Radical ◽

Tumor Cells ◽

Free Iron ◽

Radical State

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Construction of histidine-tagged yeast mitochondrial cytochrome c oxidase for facile purification of mutant forms

Biochemical Journal ◽

10.1042/bj20120116 ◽

2012 ◽

Vol 444 (2) ◽

pp. 199-204 ◽

Cited By ~ 19

Author(s):

Brigitte Meunier ◽

Amandine Maréchal ◽

Peter R. Rich

Keyword(s):

Cytochrome C ◽

Cytochrome C Oxidase ◽

Point Mutations ◽

Normal Functioning ◽

Yeast Saccharomyces Cerevisiae ◽

C Terminus ◽

Radical State ◽

Uv Visible ◽

H Channels ◽

Mutant Forms

Yeast CcO (cytochrome c oxidase) has been developed as a facile system for the production and analysis of mutants of a mitochondrial form of CcO for mechanistic studies. First, a 6H tag (His6 tag) was fused to the C-terminus of a nuclear-encoded subunit of CcO from yeast Saccharomyces cerevisiae. This allowed efficient purification of a WT (wild-type) mitochondrial CcO, 6H-WT (yeast CcO with a 6H tag on the nuclear-encoded Cox13 subunit), with a recovery yield of 45%. Its catalytic-centre activity [≈180 e·s−1 (electrons per s)], UV–visible signatures of oxidized and reduced states and ability to form the PM [‘peroxy’ (but actually a ferryl/radical state)] and F (ferryl) intermediates confirm normal functioning of the histidine-tagged protein. Point mutations were introduced into subunit I of the 6H-WT strain. All mutants were screened for their ability to assemble CcO and grow on respiratory substrate. One such mutant [6H-E243DI (the 6H-WT strain with an additional mutation of E243D in mitochondrial DNA-encoded subunit I)] was purified and showed ~50% of the 6H-WT catalytic-centre activity, consistent with the effects of the equivalent mutation in bacterial oxidases. Mutations in both the D and the H channels affect respiratory growth and these effects are discussed in terms of their putative roles in CcO mechanism.

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