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Matsunami-Nakamura R, Tamogami J, Takeguchi M, Ishikawa J, Kikukawa T, Kamo N, Nara T. Key determinants for signaling in the sensory rhodopsin II/transducer complex are different between Halobacterium salinarum and Natronomonas pharaonis. FEBS Lett 2023; 597:2334-2344. [PMID: 37532685 DOI: 10.1002/1873-3468.14711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 08/04/2023]
Abstract
The cell membrane of Halobacterium salinarum contains a retinal-binding photoreceptor, sensory rhodopsin II (HsSRII), coupled with its cognate transducer (HsHtrII), allowing repellent phototaxis behavior for shorter wavelength light. Previous studies on SRII from Natronomonas pharaonis (NpSRII) pointed out the importance of the hydrogen bonding interaction between Thr204NpSRII and Tyr174NpSRII in signal transfer from SRII to HtrII. Here, we investigated the effect on phototactic function by replacing residues in HsSRII corresponding to Thr204NpSRII and Tyr174NpSRII . Whereas replacement of either residue altered the photocycle kinetics, introduction of any mutations at Ser201HsSRII and Tyr171HsSRII did not eliminate negative phototaxis function. These observations imply the possibility of the presence of an unidentified molecular mechanism for photophobic signal transduction differing from NpSRII-NpHtrII.
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Affiliation(s)
| | - Jun Tamogami
- College of Pharmaceutical Sciences, Matsuyama University, Japan
| | - Miki Takeguchi
- College of Pharmaceutical Sciences, Matsuyama University, Japan
| | - Junya Ishikawa
- College of Pharmaceutical Sciences, Matsuyama University, Japan
| | - Takashi Kikukawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Naoki Kamo
- College of Pharmaceutical Sciences, Matsuyama University, Japan
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Toshifumi Nara
- College of Pharmaceutical Sciences, Matsuyama University, Japan
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Dai G, Geng X, Chaoluomeng, Tamogami J, Kikukawa T, Demura M, Kamo N, Iwasa T. Photocycle of Sensory Rhodopsin II from Halobacterium salinarum (HsSRII): Mutation of D103 Accelerates M Decay and Changes the Decay Pathway of a 13-cis O-like Species. Photochem Photobiol 2018. [PMID: 29512821 DOI: 10.1111/php.12917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aspartic acid 103 (D103) of sensory rhodopsin II from Halobacterium salinarum (HsSRII, or also called phoborhodopsin) corresponds to D115 of bacteriorhodopsin (BR). This amino acid residue is functionally important in BR. This work reveals that a substitution of D103 with asparagine (D103N) or glutamic acid (D103E) can cause large changes in HsSRII photocycle. These changes include (1) shortened lifetime of the M intermediate in the following order: the wild-type > D103N > D103E; (2) altered decay pathway of a 13-cis O-like species. The 13-cis O-like species, tentatively named Px, was detected in HsSRII photocycle. Px appeared to undergo branched reactions at 0°C, leading to a recovery of the unphotolyzed state and formation of a metastable intermediate, named P370, that slowly decayed to the unphotolyzed state at room temperature. In wild-type HsSRII at 0°C, Px mainly decayed to the unphotolyzed state, and the decay reaction toward P370 was negligible. In mutant D103E at 0°C, Px decayed to P370, while the recovery of the unphotolyzed state became unobservable. In mutant D103N, the two reactions proceeded at comparable rates. Thus, D103 of HsSRII may play an important role in regulation of the photocycle of HsSRII.
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Affiliation(s)
- Gang Dai
- College of Chemistry and Environmental Science, Inner Mongolia Normal University, Hohhot, 010018, China
| | - Xiong Geng
- Division of Engineering, Muroran Institute of Technology, Muroran, 050-8585, Japan
| | - Chaoluomeng
- Division of Engineering, Muroran Institute of Technology, Muroran, 050-8585, Japan
| | - Jun Tamogami
- College of Pharmaceutical Science, Matsuyama University, Matsuyama, 790-8578, Japan
| | - Takashi Kikukawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, 060-0810, Japan.,Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, 001-0021, Japan
| | - Makoto Demura
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, 060-0810, Japan.,Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, 001-0021, Japan
| | - Naoki Kamo
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Tatsuo Iwasa
- Division of Engineering, Muroran Institute of Technology, Muroran, 050-8585, Japan
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Tamogami J, Kikukawa T, Ikeda Y, Demura M, Nara T, Kamo N. Photo-induced bleaching of sensory rhodopsin II (phoborhodopsin) from Halobacterium salinarum by hydroxylamine: identification of the responsible intermediates. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2012; 106:87-94. [PMID: 22104601 DOI: 10.1016/j.jphotobiol.2011.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 10/18/2011] [Accepted: 10/21/2011] [Indexed: 05/31/2023]
Abstract
Sensory rhodopsin II from Halobacterium salinarum (HsSRII) is a retinal protein in which retinal binds to a specific lysine residue through a Schiff base. Here, we investigated the photobleaching of HsSRII in the presence of hydroxylamine. For identification of intermediate(s) attacked by hydroxylamine, we employed the flash-induced bleaching method. In order to change the concentration of intermediates, such as M- and O-intermediates, experiments were performed under varying flashlight intensities and concentrations of azide that accelerated only the M-decay. We found the proportional relationship between the bleaching rate and area under the concentration-time curve of M, indicating a preferential attack of hydroxylamine on M. Since hydroxylamine is a water-soluble reagent, we hypothesize that for M, hydrophilicity or water-accessibility increases specifically in the moiety of Schiff base. Thus, hydroxylamine bleaching rates may be an indication of conformational changes near the Schiff base. We also considered the possibility that azide may induce a small conformational change around the Schiff base. We compared the hydroxylamine susceptibility between HsSRII and NpSRII (SRII from Natronomonas pharaonis) and found that the M of HsSRII is about three times more susceptible than that of the stable NpSRII. In addition, long illumination to HsSRII easily produced M-like photoproduct, P370. We thus infer that the instability of HsSRII under illumination may be related to this increase of hydrophilicity at M and P370.
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Affiliation(s)
- Jun Tamogami
- College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan
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