Assessment of the orientation and conformation of pigments in protein binding sites from infrared difference spectra

Rohani, Leyla; Hastings, Gary

doi:10.1016/j.bbabio.2020.148366

Cited by 6 publications

(1 citation statement)

References 40 publications

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“…A similar trend is observed in calculated DDS obtained using the " ipped Q+Leu model (not shown). This may not be the case in higher level calculations using QM:MM models similar to that undertaken recently [50]. These higher-level calculations will be the subject of future research.…”

Section: Calculationsmentioning

confidence: 89%

Time-resolved FTIR difference spectroscopy for the study of photosystem I with high potential naphthoquinones incorporated into the A1 binding site 2: Identification of neutral state quinone bands

Agarwala

Hastings

2023

Photosynth Res

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Time-resolved step-scan FTIR difference spectroscopy at 77 K has been used to study cyanobacterial photosystem I (PSI) from Synechocystis sp. PCC 6803 with four high-potential, 1,4-naphthoquinones (NQs) incorporated into the A 1 binding site. The incorporated quinones are 2-chloro-NQ (2ClNQ), 2bromo-NQ (2BrNQ), 2,3-dichloro-NQ (Cl 2 NQ), and 2,3-dibromo-NQ (Br 2 NQ). For completeness 2methyl-NQ (2MNQ) was also incorporated and studied. Here we focus on spectra in the previously unexplored 1400 − 1200 cm − 1 spectral region. In this region several bands are identi ed and assigned to the neutral state of the incorporated quinones. This is important as identi cation of neutral state quinone bands in the regular 1700 − 1600 cm − 1 region has proven di cult in the past.For neutral PhQ in PSI a broad, intense band appears at 1300 cm − 1 . For the symmetric di-substituted NQs (Cl 2 NQ/Br 2 NQ) a single intense neutral state band is found at ~ 1280/1269 cm − 1 , respectively. For both mono-substituted NQs, 2ClNQ and 2BrNQ, however, two neutral state bands are observed near 1280 and 1250 cm − 1 , respectively. These observations from time-resolved spectra agree well with conclusions drawn from absorption spectra of the NQs in THF, which are also presented here. Density functional theory (DFT) based vibrational frequency calculations are also undertaken allowing an identi cation of the normal modes associated with the neutral state quinone bands.Multiple types of double difference spectra are compared and it is shown that this comparison is a potent approach for band identi cation in highly convoluted spectra.

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Section: Calculationsmentioning

confidence: 89%

Time-resolved FTIR difference spectroscopy for the study of photosystem I with high potential naphthoquinones incorporated into the A1 binding site 2: Identification of neutral state quinone bands

Agarwala

Hastings

2023

Photosynth Res

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Time-resolved FTIR difference spectroscopy for the study of photosystem I with high potential naphthoquinones incorporated into the A1 binding site

Agarwala

Makita

Hastings

2023

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Photobiological systems studied by time-resolved infrared spectroscopy (2021–2022)

Mezzetti

2023

Photochemistry

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In this review, the scientific results and the technical improvements in the last two years (2021 and 2022) in the field of time-resolved IR spectroscopy in the (sub-)ns-second timescale applied to photobiology are described. Results that appeared in early 2023 are also included. Particular attention will be paid to studies in the field of photosynthesis. After general conclusions, the perspectives in time-resolved IR applied to photobiological systems are described.

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Assessment of the orientation and conformation of pigments in protein binding sites from infrared difference spectra

Cited by 6 publications

References 40 publications

Time-resolved FTIR difference spectroscopy for the study of photosystem I with high potential naphthoquinones incorporated into the A1 binding site 2: Identification of neutral state quinone bands

Time-resolved FTIR difference spectroscopy for the study of photosystem I with high potential naphthoquinones incorporated into the A1 binding site 2: Identification of neutral state quinone bands

Time-resolved FTIR difference spectroscopy for the study of photosystem I with high potential naphthoquinones incorporated into the A1 binding site

Photobiological systems studied by time-resolved infrared spectroscopy (2021–2022)

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