TY - JOUR
T1 - Interaction of the halobacterial transducer to a halorhodopsin mutant engineered so as to bind the transducer
T2 - Cl- circulation within the extracellular channel
AU - Hasegawa, Chisa
AU - Kikukawa, Takashi
AU - Miyauchi, Seiji
AU - Seki, Akiteru
AU - Sudo, Yuki
AU - Kubo, Megumi
AU - Demura, Makoto
AU - Kamo, Naoki
PY - 2007/3
Y1 - 2007/3
N2 - An alkali-halophilic archaeum, Natronomonas pharaonis, contains two rhodopsins that are halorhodopsin (phR), a light-driven inward Cl- pump and phoborhodopsin (ppR), the receptor of negative phototaxis functioning by forming a signaling complex with a transducer, pHtrII (Sudo Y. et al., J. Mol. Biol. 357 [2006] 1274). Previously, we reported that the phR double mutant, P240T/F250YphR, can bind with pHtrII. This mutant itself can transport Cl-, while the net transport was stopped upon formation of the complex. The flash-photolysis data were analyzed by a scheme in which phR→P1→P2→P3→P 4→phR. The P3 of the wild-type and the double mutant contained two components, X- and O-intermediates. After the complex formation, however, the P3 of the double mutant lacked the X-intermediate. These observations imply that the X-intermediate (probably the N-intermediate) is the state having Cl- in the cytoplasmic binding site and that the complex undergoes an extracellular Cl- circulation because of the inhibition of formation of the X-intermediate.
AB - An alkali-halophilic archaeum, Natronomonas pharaonis, contains two rhodopsins that are halorhodopsin (phR), a light-driven inward Cl- pump and phoborhodopsin (ppR), the receptor of negative phototaxis functioning by forming a signaling complex with a transducer, pHtrII (Sudo Y. et al., J. Mol. Biol. 357 [2006] 1274). Previously, we reported that the phR double mutant, P240T/F250YphR, can bind with pHtrII. This mutant itself can transport Cl-, while the net transport was stopped upon formation of the complex. The flash-photolysis data were analyzed by a scheme in which phR→P1→P2→P3→P 4→phR. The P3 of the wild-type and the double mutant contained two components, X- and O-intermediates. After the complex formation, however, the P3 of the double mutant lacked the X-intermediate. These observations imply that the X-intermediate (probably the N-intermediate) is the state having Cl- in the cytoplasmic binding site and that the complex undergoes an extracellular Cl- circulation because of the inhibition of formation of the X-intermediate.
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U2 - 10.1562/2006-06-09-RA-916
DO - 10.1562/2006-06-09-RA-916
M3 - Article
C2 - 16978043
AN - SCOPUS:34247272464
VL - 83
SP - 293
EP - 302
JO - Photochemistry and Photobiology
JF - Photochemistry and Photobiology
SN - 0031-8655
IS - 2
ER -