This invited paper is part of the Symposium-in-Print: Photoreceptors and Signal Transduction.
Dynamics Change of Phoborhodopsin and Transducer by Activation: Study Using D75N Mutant of the Receptor by Site-directed Solid-state 13C NMR†
Article first published online: 18 MAR 2008
© 2008 The Authors. Journal Compilation. The American Society of Photobiology
Photochemistry and Photobiology
Volume 84, Issue 4, pages 921–930, July/August 2008
How to Cite
Kawamura, I., Yoshida, H., Ikeda, Y., Yamaguchi, S., Tuzi, S., Saitô, H., Kamo, N. and Naito, A. (2008), Dynamics Change of Phoborhodopsin and Transducer by Activation: Study Using D75N Mutant of the Receptor by Site-directed Solid-state 13C NMR. Photochemistry and Photobiology, 84: 921–930. doi: 10.1111/j.1751-1097.2008.00326.x
- Issue published online: 9 JUL 2008
- Article first published online: 18 MAR 2008
- Received 31 October 2007, accepted 1 January 2008
Pharaonis phoborhodopsin (ppR or sensory rhodopsin II) is a negative phototaxis receptor of Natronomonas pharaonis, and forms a complex, which transmits the photosignal into cytoplasm, with its cognate transducer (pHtrII). We examined a possible local dynamics change of ppR and its D75N mutant complexed with pHtrII, using solid-state 13C NMR of [3-13C]Ala- and [1-13C]Val-labeled preparations. We distinguished Ala Cβ13C signals of relatively static stem (Ala221) in the C-terminus of the receptors from those of flexible tip (Ala228, 234, 236 and 238), utilizing a mutant with truncated C-terminus. The local fluctuation frequency at the C-terminal tip was appreciably decreased when ppR was bound to pHtrII, while it was increased when D75N, that mimics the signaling state because of disrupted salt bridge between C and G helices prerequisite for the signal transfer, was bound to pHtrII. This signal change may be considered with the larger dissociation constant of the complex between pHtrII and M-state of ppR. At the same time, it turned out that fluctuation frequency of cytoplasmic portion of pHtrII is lowered when ppR is replaced by D75N in the complex with pHtrII. This means that the C-terminal tip partly participates in binding with the linker region of pHtrII in the dark, but this portion might be released at the signaling state leading to mutual association of the two transducers in the cytoplasmic regions within the ppR/pHtrII complex.