Intermediate and stable redox states of cytochrome c studied by low temperature resonance Raman spectroscopy

Cartling, Bo

doi:10.1016/s0006-3495(83)84340-9

Cited by 37 publications

(43 citation statements)

References 34 publications

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“…Although at ambient temperature additional UV‐irradiation was used to continuously recover Rh‐Bl from Rh‐UV, a photostationary mixture between Rh‐UV and Rh‐Bl is established but only the spectrum of the latter species is resonantly enhanced at 514 nm. Compared to this spectrum, at low temperature only minor differences are noted which refer to small frequency upshifts for a few bands and variations of the relative intensities as typically observed in RR experiments of chromoproteins [9]. There are no indications for further structural changes of the cofactor.…”

Section: Resultsmentioning

confidence: 64%

Photochemical chromophore isomerization in histidine kinase rhodopsin HKR1

et al. 2015

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a b s t r a c tHistidine kinase rhodopsin 1 is a photoreceptor in green algae functioning as a UV-light sensor. It switches between a UV-absorbing state (Rh-UV) and a blue-absorbing state (Rh-Bl) with a protonated retinal Schiff base (RSB) cofactor in a mixture of 13-trans,15-anti and 13-cis,15-syn isomers.The present spectroscopic study now shows that cofactor-protein assembly stabilizes the protonated 13-trans,15-anti RSB isomer. Formation of the active photoswitch requires the photoinduced conversion to Rh-UV. The transitions between the Rh-Bl isomers and the deprotonated 13-cis,15-anti and 13-trans,15-syn isomers of Rh-UV proceed via multiple photoisomerizations of one or simultaneously two double bonds.

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Section: Resultsmentioning

confidence: 64%

Photochemical chromophore isomerization in histidine kinase rhodopsin HKR1

et al. 2015

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“…proteins form a second domain because they are heme containing proteins that exhibit the resonance Raman effect. 39 The remaining nine biological materials form the third domain and are enlarged in Fig. 3b in order to provide a better visual understanding of their relationships.…”

Section: Resultsmentioning

confidence: 99%

Waterborne Pathogen Detection Using Raman Spectroscopy

et al. 2008

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Raman spectroscopy is being evaluated as a candidate technology for waterborne pathogen detection. We have investigated the impact of key experimental and background interference parameters on the bacterial species level identification performance of Raman detection. These parameters include laser-induced photodamage threshold, composition of water matrix, and organism aging in water. The laser-induced photodamage may be minimized by operating a 532 nm continuous wave laser excitation at laser power densities below 2300 W/cm(2) for Grampositive Bacillus atrophaeus (formerly Bacillus globigii, BG) vegetative cells, 2800 W/cm(2) for BG spores, and 3500 W/cm(2) for Gram-negative E. coli (EC) organisms. In general, Bacillus spore microorganism preparations may be irradiated with higher laser power densities than the equivalent Bacillus vegetative preparations. In order to evaluate the impact of background interference and organism aging, we selected a biomaterials set comprising Gram-positive (anthrax simulants) organisms, Gram-negative (plague simulant) organisms, and proteins (toxin simulants) and constructed a Raman signature classifier that identifies at the species level. Subsequently, we evaluated the impact of tap water and storage time in water (aging) on the classifier performance when characterizing B. thuringiensis spores, BG spores, and EC cell preparations. In general, the measured Raman signatures of biological organisms exhibited minimal spectral variability with respect to the age of a resting suspension and water matrix composition. The observed signature variability did not substantially degrade discrimination performance at the genus and species levels. In addition, Raman chemical imaging spectroscopy was used to distinguish a mixture of BG spores and EC cells at the single cell level.

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“…Since most proteins of interest for extracellular electron transfer such as hydrogenases and multiheme cytochromes contain metal centres that are highly Raman active, CRM is particularly suitable for studies of electrochemically active microbial aggregates. [41][42][43] In addition, as heme groups in cyt c possess unique vibrational signatures that should allow their redox states to be clearly distinguished, 17,44,45 we hypothesized that CRM would enable mapping changes in redox forms of cyt c within whole active biofilms. To test this hypothesis, we performed spectral acquisition on anodic biofilms with the same setup as used previously, but in addition, we used the potentiostat to set fixed anodic potentials, as detailed in the Materials and methods section.…”

Section: Effect Of Electrode Polarization On the Resonance Raman Spec...mentioning

confidence: 99%

Non-invasive characterization of electrochemically active microbial biofilms using confocal Raman microscopy

Virdis

Harnisch

Batstone

et al. 2012

Energy Environ. Sci.

108

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Electrochemically active biofilms rely on microorganisms capable of extracellular electron transfer. Such biofilms are involved in the dissimilatory reduction of metal oxides in natural environments as well as electricity driving and driven processes at the electrodes of microbial bioelectrochemical systems. In this work we present the application of confocal Raman microscopy (CRM) as a non-invasive, label-free, and in vivo characterization method of acetate oxidizing anodic biofilms, grown from primary wastewater inoculum and dominated by Geobacter species (>85% of sequences analysed using pyrotag sequencing). Using the resonance Raman effect of the heme protein cytochrome c (Cyt c)-an ubiquitous component of extracellular electron transfer reactions-it was possible to collect characteristic spectral information of electrochemically active biofilms at pixel integration times of 0.2 s and an excitation wavelength of 532 nm. This allowed monitoring of biofilm development at different growth stages, without impacting its structural or metabolic activity. Furthermore, we demonstrate the possibility of non-invasive investigation of the spatial redox electrochemistry (up to a compositional level) of electrochemically active biofilms, as we observed significant changes in the vibrational properties of Cyt c resulting from shifts in the anodic potential between different redox conditions. Compared to conventional methods requiring destructive sample manipulation and fixation, the proposed approach based on CRM allows the non-invasive analysis of microbial aggregates with minimal sample preparation or prior knowledge of the sample

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Intermediate and stable redox states of cytochrome c studied by low temperature resonance Raman spectroscopy

Cited by 37 publications

References 34 publications

Photochemical chromophore isomerization in histidine kinase rhodopsin HKR1

Photochemical chromophore isomerization in histidine kinase rhodopsin HKR1

Waterborne Pathogen Detection Using Raman Spectroscopy

Non-invasive characterization of electrochemically active microbial biofilms using confocal Raman microscopy

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