scholarly journals A nanosecond time-resolved XFEL analysis of structural changes associated with CO release from cytochrome c oxidase

2017 ◽  
Vol 3 (7) ◽  
pp. e1603042 ◽  
Author(s):  
Atsuhiro Shimada ◽  
Minoru Kubo ◽  
Seiki Baba ◽  
Keitaro Yamashita ◽  
Kunio Hirata ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Structural Changes ◽  
Time Resolved

scholarly journals Probing the Proton-Loading Site of Cytochrome C Oxidase Using Time-Resolved Fourier Transform Infrared Spectroscopy

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3393
Author(s):  
Elena Gorbikova ◽  
Sergey A. Samsonov ◽  
Ruslan Kalendar
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Fourier Transform Infrared Spectroscopy ◽  
Paracoccus Denitrificans ◽  
Fourier Transform Infrared ◽  
Double Difference ◽  
Time Resolved ◽  
Fast Kinetic

Crystal structure analyses at atomic resolution and FTIR spectroscopic studies of cytochrome c oxidase have yet not revealed protonation or deprotonation of key sites of proton transfer in a time-resolved mode. Here, a sensitive technique to detect protolytic transitions is employed. In this work, probing a proton-loading site of cytochrome c oxidase from Paracoccus denitrificans with time-resolved Fourier transform infrared spectroscopy is presented for the first time. For this purpose, variants with single-site mutations of N131V, D124N, and E278Q, the key residues in the D-channel, were studied. The reaction of mutated CcO enzymes with oxygen was monitored and analyzed. Seven infrared bands in the “fast” kinetic spectra were found based on the following three requirements: (1) they are present in the “fast” phases of N131V and D124N mutants, (2) they have reciprocal counterparts in the “slow” kinetic spectra in these mutants, and (3) they are absent in “fast” kinetic spectra of the E278Q mutant. Moreover, the double-difference spectra between the first two mutants and E278Q revealed more IR bands that may belong to the proton-loading site protolytic transitions. From these results, it is assumed that several polar residues and/or water molecule cluster(s) share a proton as a proton-loading site. This site can be propionate itself (holding only a fraction of H+), His403, and/or water cluster(s).

scholarly journals Towards time-resolved structural studies of ba3-type cytochrome c oxidase

2018 ◽  
Vol 1859 ◽  
pp. e72
Author(s):  
Cecilia Safari ◽  
Swagatha Ghosh ◽  
Rebecka Andersson ◽  
Gisela Brändén
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Structural Studies ◽  
Time Resolved

Time-resolved FTIR Spectroscopy on Fully-Reduced CO Bound Cytochrome c Oxidase

2000 ◽  
Vol 28 (5) ◽  
pp. A189-A189
Author(s):  
D. Heitbrink ◽  
J. Heberle ◽  
C. Bolwien ◽  
H. Sigurdson ◽  
P. Brzesinski
Keyword(s):  
Cytochrome C ◽  
Ftir Spectroscopy ◽  
Cytochrome C Oxidase ◽  
Time Resolved

scholarly journals Time-Resolved Surface-Enhanced IR-Absorption Spectroscopy of Direct Electron Transfer to Cytochrome c Oxidase from R. sphaeroides

2013 ◽  
Vol 105 (12) ◽  
pp. 2706-2713 ◽  
Author(s):  
Andreas Schwaighofer ◽  
Christoph Steininger ◽  
David M. Hildenbrandt ◽  
Johannes Srajer ◽  
Christoph Nowak ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Absorption Spectroscopy ◽  
Direct Electron Transfer ◽  
Ir Absorption ◽  
Time Resolved ◽  
Surface Enhanced

scholarly journals Operando Infrared Spectroscopy for the Analysis of Gas-processing Metalloenzymes

2020 ◽  
Author(s):  
Sven Timo Stripp
Keyword(s):  
Infrared Spectroscopy ◽  
Cytochrome C ◽  
Ambient Temperature ◽  
Cytochrome C Oxidase ◽  
Structural Changes ◽  
Attenuated Total Reflection ◽  
Invasive Technique ◽  
Difference Spectra ◽  
Gas Processing ◽  
Temperature And Pressure

Earth-abundant transition metals like iron, nickel, copper, molybdenum, and vanadium have been identified as essential constituents of the cellular gas metabolism in all kingdoms of life. Associated with biological macromolecules, gas-processing metalloenzymes (GPMs) are formed that catalyse a variety of redox reactions. This includes the reduction of O2 to water by cytochrome c oxidase (‘complex IV’), the reduction of N2 to NH4 by nitrogenase, as well as the reduction of protons to H2 (and oxidation of the later) by hydrogenase. GPMs perform at ambient temperature and pressure, in the presence of water, and often extremely low educt concentrations, thus serving as natural examples for efficient catalysis. Facilitating the design of biomimetic catalysts, biophysicist thrive to understand the reaction principles of GPMs making use of various techniques. In this perspective, I will introduce Fourier-transform infrared spectroscopy in attenuated total reflection configuration (ATR FTIR) for the analysis of GPMs like cytochrome c oxidase, nitrogenase, and hydrogenase. Infrared spectroscopy provides information about the geometry and redox state of the catalytic cofactors, the protonation state of amino acid residues, the hydrogen-bonding network, and protein structural changes. I developed an approach to probe and trigger the reaction of GPMs by gas exchange experiments, exploring the reactivity of these enzymes with their natural reactants. This allows recording sensitive ATR FTIR difference spectra with seconds time resolution. Finally yet importantly, infrared spectroscopy is an electronically non-invasive technique that allows investigating protein samples under biologically relevant conditions, i.e., at ambient temperature and pressure, and in the presence of water.

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