Calculated vibrational properties of semiquinones in the A1 binding site in photosystem I

Rohani, Leyla; Makita, Hiroki; Levitz, Andrew; Henary, Maged; Hastings, Gary

doi:10.1016/j.bbabio.2019.07.003

Cited by 9 publications

(5 citation statements)

References 43 publications

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“…In these cases, the theoretical approaches are basically the only way to achieve band attribution. DFT (see for instance Mezzetti et al [73]), QM/MM (see for instance Rohani et al [74]) or more advanced calculations (Macaluso et al [75]; Petrone et al [76]) become particularly useful.…”

Section: Sample Preparation and Data Analysismentioning

confidence: 99%

Time-resolved infrared absorption spectroscopy applied to photoinduced reactions: how and why

Mezzetti

Schnee

Lapini³

et al. 2022

Photochem Photobiol Sci

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Time-resolved infrared (IR) spectroscopy is a widely used technique in the investigation of photoinduced reactions, given its capabilities of providing structural information about the presence of intermediates and the reaction mechanism. Despite the fact that it is used in several fields since the '80s, the communication between the different scientific communities (photochemists, photobiologists, etc.) has been to date quite limited. In some cases, this lack of communication happened-and still happens-even inside the same scientific community (for instance between specialists in ultrafast ps/fs IR and those in "fast" ns/µs/ms IR). Even more surprising is the difficulty of non-specialists to understand the potential of time-resolved IR spectroscopy, despite the fact that IR spectroscopy is normally taught to all chemistry and material science students, and to several biology and physics students. This tutorial review aims at helping to solve these issues, first by providing a comprehensive but reader-friendly overview of the different techniques, and second, by focusing on five "case studies" (from photobiology, gas-phase photocatalysis, photochemistry, semiconductors and metal-carbonyl complexes). We are confident that this approach can help the reader-whichever is its background-to understand the capabilities of time-resolved IR spectroscopy to study the mechanism of photoinduced reactions.

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Section: Sample Preparation and Data Analysismentioning

confidence: 99%

Time-resolved infrared absorption spectroscopy applied to photoinduced reactions: how and why

Mezzetti

Schnee

Lapini³

et al. 2022

Photochem Photobiol Sci

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“…The 1494 cm -1 band in the TRSS FTIR DS at 77 K (Fig. 2C) is due to the C 1 O group of PhQin the A 1A binding site (Rohani et al 2019). For the 1494 cm -1 absorption change, 72% of the positive, ashinduced absorption change decays on the nanosecond timescale, with 40 and 32% of the amplitude being associated with the 33 and 364 ns time constants, respectively (Fig.…”

Section: Discussionmentioning

confidence: 95%

“…These bands are therefore associated with A 1 -. The bands at 1495 and 1415 cm -1 are well known to be due to stretching vibrations of the C 1 O and C 4 O groups of the phyllosemiquinone anion in the A 1A binding site(Hastings 2015;Rohani et al 2019). Given the similarity in the frequencies of the bands in the (P700 + -P700) FTIR DS at 295 and 77 K (Fig.2C), it is likely that the phyllosemiquinone anion bands will also be at similar frequencies at 77 and 295 K. We therefore expect to observe TRIR absorption changes at ~ 1495 and ~ 1415 cm -1 associated with A 1A reduction and recovery at RT.…”

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confidence: 99%

Nanosecond Time-Resolved Infrared Spectroscopy for the Study of Electron Transfer in Photosystem I

Mäusle

Agarwala

Eichmann

et al. 2023

Preprint

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Microsecond time-resolved step-scan FTIR difference spectroscopy was used to study photosystem I (PSI) from Thermosynechococcus vestitus BP-1 (T. vestitus, formerly known as T. elongatus) at 77 K. Photoaccumulated (P700+ – P700) FTIR difference spectra were also obtained for PSI from T. vestitus at both 77 and 293 K. The FTIR difference spectra are presented here for the first time. To greatly extend upon these FTIR studies nanosecond time-resolved infrared difference spectroscopy was also used to study PSI from T. vestitus at 293 K. Nanosecond infrared spectroscopy has never been used to study PSI samples at physiological temperatures, and here it is shown that such an approach has great value as it allows a direct probe of electron transfer down both branches in PSI. In PSI at 293 K, the infrared flash-induced absorption changes indicate electron transfer down the A- and B-branches is characterized by time constants of 33 and 364 ns, respectively, in good agreement with visible spectroscopy studies. These time constants are associated with forward electron transfer from A1– to FX on the B- and A-branches, respectively. At several infrared wavelengths flash-induced absorption changes at 293 K recover in tens to hundreds of milliseconds. The dominant decay phase is characterized by a lifetime of 128 ms. These millisecond changes are assigned to radical pair recombination reactions, with the changes being associated primarily with P700+ rereduction. This conclusion follows from the observation that the millisecond infrared spectrum is very similar to the photoaccumulated (P700+ – P700) FTIR difference spectrum.

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“…These bands are therefore associated with A 1 – . The bands at 1495 and 1415 cm –1 are well known to be due to stretching vibrations of the C 1 O and C 4 O groups of the phyllosemiquinone anion in the A 1A binding site (Hastings 2015 ; Rohani et al 2019 ). Given the similarity in the frequencies of the bands in the (P700 + –P700) FTIR DS at 293 and 77 K (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The 1494 cm –1 band in the TRSS FTIR DS at 77 K (Fig. 2 C) is due to the C 1 O group of PhQ – in the A 1A binding site (Rohani et al 2019 ). For the 1494 cm –1 absorption change, 72% of the positive, flash-induced absorption change decays on the nanosecond timescale, with 40 and 32% of the amplitude being associated with the 33 and 364 ns time constants, respectively (Fig.…”

Section: Discussionmentioning

confidence: 99%

Nanosecond time-resolved infrared spectroscopy for the study of electron transfer in photosystem I

et al. 2023

Self Cite

View full text Add to dashboard Cite

Microsecond time-resolved step-scan FTIR difference spectroscopy was used to study photosystem I (PSI) from Thermosynechococcus vestitus BP-1 (T. vestitus, formerly known as T. elongatus) at 77 K. In addition, photoaccumulated (P700+–P700) FTIR difference spectra were obtained at both 77 and 293 K. The FTIR difference spectra are presented here for the first time. To extend upon these FTIR studies nanosecond time-resolved infrared difference spectroscopy was also used to study PSI from T. vestitus at 296 K. Nanosecond infrared spectroscopy has never been used to study PSI samples at physiological temperatures, and here it is shown that such an approach has great value as it allows a direct probe of electron transfer down both branches in PSI. In PSI at 296 K, the infrared flash-induced absorption changes indicate electron transfer down the B- and A-branches is characterized by time constants of 33 and 364 ns, respectively, in good agreement with visible spectroscopy studies. These time constants are associated with forward electron transfer from A1– to FX on the B- and A-branches, respectively. At several infrared wavelengths flash-induced absorption changes at 296 K recover in tens to hundreds of milliseconds. The dominant decay phase is characterized by a lifetime of 128 ms. These millisecond changes are assigned to radical pair recombination reactions, with the changes being associated primarily with P700+ rereduction. This conclusion follows from the observation that the millisecond infrared spectrum is very similar to the photoaccumulated (P700+–P700) FTIR difference spectrum.

show abstract

Calculated vibrational properties of semiquinones in the A1 binding site in photosystem I

Cited by 9 publications

References 43 publications

Time-resolved infrared absorption spectroscopy applied to photoinduced reactions: how and why

Time-resolved infrared absorption spectroscopy applied to photoinduced reactions: how and why

Nanosecond Time-Resolved Infrared Spectroscopy for the Study of Electron Transfer in Photosystem I

Nanosecond time-resolved infrared spectroscopy for the study of electron transfer in photosystem I

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