Picosecond Time-Resolved Ultraviolet Resonance Raman Spectroscopy of Bacteriorhodopsin: Primary Protein Response to the Photoisomerization of Retinal

Mizuno, Maya; Shibata, Mikihiro; Yamada, Junya; Kandori, Hideki; Mizutani, Yasuhisa

doi:10.1021/jp904388w

Cited by 26 publications

(71 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, we used picosecond time-resolved ultraviolet RR (UVRR) spectroscopy to selectively measure Raman spectra of the tryptophan and tyrosine residues in NpHR. This is a powerful technique for revealing the initial protein response to chromophore isomerization, as demonstrated previously using several microbial rhodopsins 14–18 . In the previous studies, we reported the protein response for cation (proton)-pumping 14 and photosensory rhodopsins 15–17 .…”

Section: Introductionsupporting

confidence: 51%

Effect of a bound anion on the structure and dynamics of halorhodopsin from Natronomonas pharaonis

Mizuno

Shimoo

Kandori

et al. 2019

Structural Dynamics

Self Cite

View full text Add to dashboard Cite

Active ion transport across membranes is vital to maintaining the electrochemical gradients of ions in cells and is mediated by transmembrane proteins. Halorhodopsin (HR) functions as a light-driven inward pump for chloride ions. The protein contains all-trans-retinal bound to a specific lysine residue through a protonated Schiff base. Interaction between the bound chloride ion and the protonated Schiff base is crucial for ion transport because chloride ion movement is driven by the flipping of the protonated Schiff base upon photoisomerization. However, it remains unknown how this interaction evolves in the HR photocycle. Here, we addressed the effect of the bound anion on the structure and dynamics of HR from Natronomonas pharaonis in the early stage of the photocycle. Comparison of the chloride-bound, formate-bound, and anion-depleted forms provided insights into the interaction between the bound anion and the chromophore/protein moiety. In the unphotolyzed state, the bound anion affects the π-conjugation of the polyene chain and the hydrogen bond of the protonated Schiff base of the retinal chromophore. Picosecond time scale measurements showed that the band intensities of the W16 and W18 modes of the tryptophan residues decreased instantaneously upon photoexcitation of the formate-bound form. In contrast, these intensity decreases were delayed for the chloride-bound and anion-depleted forms. These observations suggest the stronger interactions of the bound formate ion with the retinal chromophore and the chromophore pocket. On the nanosecond to microsecond timescales, we found that the interaction between the protonated Schiff base and the bound ion is broken upon formation of the K intermediate and is recovered following translocation of the bound anion toward the protonated Schiff base in the L intermediate. Our results demonstrate that the hydrogen-bonding ability of the bound anion plays an essential role in the ion transport of light-driven anion pumps.

show abstract

Section: Introductionsupporting

confidence: 51%

Effect of a bound anion on the structure and dynamics of halorhodopsin from Natronomonas pharaonis

Mizuno

Shimoo

Kandori

et al. 2019

Structural Dynamics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Its existence is required to reconcile the time-resolved 29 and the low-temperature FTIR data 23,79 . A time constant of 40–100 ps was proposed for such a transition based on fast measurements in Raman 32 , IR 25 and UV 22 . Such 70±30 ps 22,25 time constant is consistent with conclusions from the photodamage experiments 45 .…”

Section: Discussionmentioning

confidence: 99%

Two Bathointermediates of the Bacteriorhodopsin Photocycle, from Time-Resolved Nanosecond Spectra in the Visible

Dioumaev

Lanyi

2009

J. Phys. Chem. B

View full text Add to dashboard Cite

Time-resolved measurements were performed on wild-type bacteriorhodopsin with an optical multi-channel analyzer in the spectral range of 350–735 nm, from 100 ns to the photocycle completion, at four temperatures in the 5–30 °C range. The intent was to examine the possibility of two K-like bathochromic intermediates and to obtain their spectra and kinetics in the visible. The existence of a second K-like intermediate, termed KL, had been postulated (Shichida et al., BBA 723:240–246, 1983) to reconcile inconsistencies in data in the pico- and microsecond time-domains. However, introduction of KL led to a controversy since neither its visible spectrum nor its kinetics could be confirmed. Infra-red data (Dioumaev & Braiman, J. Phys. Chem., B, 101:1655–1662, 1997), revealed a state, which might have been considered a homologue to KL but it had a kinetic pattern different from that of the earlier proposed KL. Here we characterize two distinct K-like intermediates, KE (“early”) and KL (“late”), by their spectra and kinetics in the visible as revealed by global kinetic analysis. The KE-to-KL transition has a time constant of ~250 ns at 20 °C, and describes a shift from KE with λmax at ~600 nm and extinction of ~56,000 M−1·cm−1 to KL with λmax at ~590 nm and extinction of ~50,000 M−1·cm−1. The temperature dependence of this transition is characterized by an enthalpy of activation ΔH# ~ 40 kJ/mol, and a positive entropy of activation ΔS#/R = ~4. The consequences of multiple K-like states for interpreting the spectral evolution in the early stages of the photocycle are discussed.

show abstract

“…The existence of more than one K-like intermediate is supported by evidence from the variety of experimental methods: in visible 14,16-20 , UV 21 , and FTIR spectroscopy 15,22-28 , resonance Raman 29-31 , CARS 32 , and photoelectric measurements 33 . The necessity for more than one K-like intermediates has been evident since early eighties 14,15 but the question on their number has not been settled, and most authors restrict their discussions to the possibility of two different K-like states 14-18,21-31 . However, two K-like states are not enough to account for the changes during the early stages of the photocycle, and the pair of K-like intermediates described by time-resolved 24-28 FTIR spectroscopy cannot be the same as the pair of intermediates characterized by low-temperature FTIR 15,34 .…”

Section: Introductionmentioning

confidence: 92%

Low-Temperature FTIR Study of Multiple K Intermediates in the Photocycles of Bacteriorhodopsin and Xanthorhodopsin

2010

View full text Add to dashboard Cite

Low-temperature FTIR spectroscopy of bacteriorhodopsin and xanthorhodopsin was used to elucidate the number of K-like bathochromic states, their sequence, and their contributions to the photo-equilibrium mixtures created by illumination at 80-180K. We conclude that in bacteriorhodopsin the photocycle includes three distinct K-like states in the sequence: bR→hvI∗→J→K0→KE→KL→L→…, and similarly in xanthorhodopsin. K0 is the main fraction in the mixture at 77K that is formed from J. K0 becomes thermally unstable above ~50K in both proteins. At 77K both J-to-K0 and K0-to-KE transitions occur and, contrarily to long-standing belief, cryogenic trapping at 77K does not produce a pure K state but a mixture of the two states, K0 and KE, with contributions from KE of ~15% and ~10% in the two retinal-proteins, respectively. Raising the temperature leads to increasing conversion of K0 to KE, and the two states coexist (without contamination from non K-like states) in the 80-140K range in bacteriorhodopsin, and in the 80-190K range in xanthorhodopsin. Temperature perturbation experiments in these regions of coexistence revealed that in spite of the observation of apparently stable mixtures of K0 and KE, the two states are not in thermally-controlled equilibrium. The K0-to-KE transition is unidirectional, and the partial transformation to KE is due to distributed kinetics, which governs the photocycle dynamics at temperatures below ~245K. From spectral deconvolution we conclude that the KE state, which is increasingly present at higher temperatures, is the same intermediate that is detected by time-resolved FTIR prior to its decay, on a time-scale of hundreds nanoseconds at ambient temperature, into the KL state. We were unable to trap the latter separately from KE at low temperature, due to the slow distributed kinetics and the increasingly faster overlapping formation of L state. Formation of the two consecutive K-like states in both proteins is accompanied by distortion of two different weakly bound water molecules: one in K0, the other in KE. The first, well-documented in bacteriorhodopsin at 77K where K0 dominates, was assigned to water 401 in bacteriorhodopsin. The other water molecule, whose participation has not been described previously, is disturbed on the next step of the photocycle, in KE, in both proteins. In bacteriorhodopsin the most likely candidate is water 407. However, unlike bacteriorhodopsin, the crystal structure of xanthorhodopsin lacks homologous weakly-bound water molecules.

show abstract

Picosecond Time-Resolved Ultraviolet Resonance Raman Spectroscopy of Bacteriorhodopsin: Primary Protein Response to the Photoisomerization of Retinal

Cited by 26 publications

References 65 publications

Effect of a bound anion on the structure and dynamics of halorhodopsin from Natronomonas pharaonis

Effect of a bound anion on the structure and dynamics of halorhodopsin from Natronomonas pharaonis

Two Bathointermediates of the Bacteriorhodopsin Photocycle, from Time-Resolved Nanosecond Spectra in the Visible

Low-Temperature FTIR Study of Multiple K Intermediates in the Photocycles of Bacteriorhodopsin and Xanthorhodopsin

Contact Info

Product

Resources

About