Solid-State NMR Studies of Two Backbone Conformations at Tyr185 as a Function of Retinal Configurations in the Dark, Light, and Pressure Adapted Bacteriorhodopsins

Kawamura, Izuru; Kihara, Naoki; Ohmine, Masato; Nishimura, Katsuyuki; Tuzi, Satoru; Saitô, Hazime; Naito, Akira

doi:10.1021/ja0664887

Cited by 31 publications

(26 citation statements)

References 17 publications

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“…In addition, it has recently been reported that fast MAS causes structural changes and motional change in membrane proteins through centrifugal pressure. 1,2 Therefore, it is important to clarify the influence of MAS on the 1 H spectra and T 1 H so that the actual molecular motion of the elastomers can be understood.…”

Section: Introductionmentioning

confidence: 99%

Influence of magic angle spinning on T1H of SBR studied by solid state 1H NMR

Asano

Hori

Kitamura

et al. 2012

Polym J

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We have investigated the influence of the high centrifugal pressure caused by fast magic-angle spinning (MAS) on the molecular motion of styrene-butadiene rubbers (SBR) filled with SiO 2 (SBR/Si composite) though solid-state magic-angle spinning nuclear magnetic Resonance ( 1 H MAS NMR) measurements. Because the 1 H-1 H dipolar interaction of elastomers is weak compared with that of glassy polymers, a narrower 1 H linewidth is observed under fast MAS. The temperature dependence of the 1 H spin-lattice relaxation time (T 1 H ) revealed that the T 1 H minimum increases with the MAS rate. Furthermore, we observed a difference in the temperature dependence of T 1 H between end-chain-modified SBR and normal (unmodified) SBR in the SBR/Si composites. The temperature dependence of T 1 H is described by the Bloembergen-Purcell-Pound theory, with the assumption that the correlation time obeys the Williams-Landel-Ferry empirical theory. The fitting showed that the molecular motion does not change significantly until a MAS rate of 20 kHz, with the motional mode changing considerably at a MAS rate of 25 kHz. The motion of SBR in the unmodified SBR/Si composite was greatly affected by the fast MAS rates. Furthermore, the plot of the estimated centrifugal pressure versus the T 1 H minimum resembled the stress-strain curve. This result enables the detection of macroscopic physical deformation by the microscopic parameter INTRODUCTIONSolid-state NMR is useful for the investigation of the molecular motion of the functional groups of elastomers and polymers. In particular, the recent development of the magic-angle spinning (MAS) technique allows a sample rotor to be spun much faster than 20 kHz. Thus, we can detect the high-resolution 1 H signals of rubbers and elastomers under the fast rates that are possible in MAS because these fast MAS rates effectively reduce the signal broadening that arises from the relatively weak 1 H-1 H dipolar interaction of elastomers (in comparison with that of glassy solid polymers).Generally, spin-lattice relaxation time (T 1 ) is observed to study molecular motion. In the case of rare spins such as 13 C, however, it is time-consuming to observe the signals and measure an accurate T 1 with a good signal-to-noise ratio. In contrast, proton signals are intense enough to allow quick analysis of molecular motion through the T 1 measurement. However, for a glassy solid polymer, the strong 1 H-1 H dipolar interaction obscures the individual functional group signals, even with fast MAS. For rubbers and elastomers under fast MAS, in contrast, each peak assigned to a respective functional group can be detected because of the weak 1 H-1 H dipolar interaction. Furthermore, it is easy to detect 1 H-T 1 ( 1 H spin-lattice relaxation time (T 1 H )) accurately. In contrast, it is well known that MAS causes the temperature of the inner sample to increase because of friction between the MAS and the air. In addition, it has recently been reported that fast MAS causes

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Section: Introductionmentioning

confidence: 99%

Influence of magic angle spinning on T1H of SBR studied by solid state 1H NMR

Asano

Hori

Kitamura

et al. 2012

Polym J

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“…The change in the local dynamics in the vicinity of retinal is closely related to the conformational change of Tyr185 in bR, as observed by solid-state MAS NMR. 7 The effects of pressure on the change in the dynamics of bR appeared even in the low-pressure range of fast MAS. It is stressed that two retinal isomers, all-trans and 13-cis, 15-syn configurations, coexist in bR in a population ratio close to 1, leading to the conclusion that both isomers have the same energy levels.…”

Section: Resultsmentioning

confidence: 97%

“…Thus, the retinal configurations in bR indicate that it takes 60 h for the pressure to reach equilibrium in the fast MAS experiments, and we can distinguish pressure-adapted bR from dark-adapted bR. 7 The pressure applied to the sample packed in the 4 mm rotor at an MAS-spinning frequency of 12 kHz was calculated to be 63 bar along the inner rotor wall according to the following equation:…”

Section: Resultsmentioning

confidence: 99%

“…in the vicinity of retinal corresponding to the all-trans and 13-cis retinal configurations in the dark-adapted bR as disclosed by REDOR-filtered 13 C NMR spectra. 7 The results showed that the signal intensity at 173.4 p.p.m. for the 13-cis, 15-syn retinal state increased considerably with the long accumulation time under the MAS condition, which is related to the large population of the 13-cis, 15-syn configuration in pressure-adapted bR.…”

Section: Introductionmentioning

confidence: 97%

“…Therefore, we performed solid-state NMR studies by applying pressure as perturbations to a sample. 6,7 Recently, we developed in-situ photo-irradiated solid-state NMR to induce the photo excitation and efficiently detected the photo-activated intermediate of a photoreceptor protein. 8 Bacteriorhodopsin (bR) in a purple membrane (PM) of H. salinarum reveals a light-driven proton pump during the photoisomerization of retinal.…”

Section: Introductionmentioning

confidence: 99%

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Change in local dynamics of bacteriorhodopsin with retinal isomerization under pressure as studied by fast magic angle spinning NMR

Kawamura

Yamaguchi

Nishikawa

et al. 2012

Polym J

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Bacteriorhodopsin (bR) has a retinal with all-trans and 13-cis, 15-syn configurations whose isomeric ratio is close to 1 in the dark-adapted bR, and the population of the 13-cis, 15-syn configuration can be increased under pressure. In our previous study, we applied pressure to bR using centrifugal force introduced by sample spinning and demonstrated that the 15 N nuclear magnetic resonance (NMR) signal intensity of the Schiff base in 13-cis, 15-syn retinal increased. In this study, we demonstrate a pressure-induced change in the local dynamics of the protein side in the vicinity of retinal. In the 13 C dipolar decoupling and magic angle-spinning NMR spectra of [3-13 C]Ala-labeled bR under fast spinning at 10 and 12 kHz, corresponding to 44 and 63 bar, respectively, the 13 C NMR signal at 16.6 p.p.m. appeared prominently as a sharp peak. This peak is assigned to Ala81 and Ala84 residues located in the vicinity of the retinal. It was observed that the change in the local dynamics in the vicinity of the retinal was caused by the applied pressure. These experiments demonstrate that fast magic angle spinning in NMR provides a pressure source for investigating the structure and change in the dynamics of biomacromolecules.

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Color‐Discriminating Retinal Configurations of Sensory Rhodopsin I by Photo‐Irradiation Solid‐State NMR Spectroscopy

et al. 2014

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SRI (sensory rhodopsin I) can discriminate multiple colors for the attractant and repellent phototaxis. Studies aimed at revealing the color-dependent mechanism show that SRI is a challenging system not only in photobiology but also in photochemistry. During the photoreaction of SRI, an Mintermediate (attractant) transforms into a P-intermediate (repellent) by absorbing blue light. Consequently, SRI then cycles back to the G-state. The photoreactions were monitored with the 13 C NMR signals of [20-13 C]retnal-SrSRI using in situ photo-irradiation solid-state NMR spectroscopy. The M-intermediate was trapped at À40 8C by illumination at 520 nm. It was transformed into the P-intermediate by subsequent illumination at 365 nm. These results reveal that the G-state could be directly transformed to the P-intermediate by illumination at 365 nm. Thus, the stationary trapped M-and P-intermediates are responsible for positive and negative phototaxis, respectively.

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Solid-State NMR Studies of Two Backbone Conformations at Tyr185 as a Function of Retinal Configurations in the Dark, Light, and Pressure Adapted Bacteriorhodopsins

Cited by 31 publications

References 17 publications

Influence of magic angle spinning on T1H of SBR studied by solid state 1H NMR

Influence of magic angle spinning on T1H of SBR studied by solid state 1H NMR

Change in local dynamics of bacteriorhodopsin with retinal isomerization under pressure as studied by fast magic angle spinning NMR

Color‐Discriminating Retinal Configurations of Sensory Rhodopsin I by Photo‐Irradiation Solid‐State NMR Spectroscopy

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