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Structural insights into the early steps of receptor—transducer signal transfer in archaeal phototaxis
Author(s) -
Wegener AnsgarA.,
Klare Johann P.,
Engelhard Martin,
Steinhoff HeinzJürgen
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.19.5312
Subject(s) - biology , phototaxis , transducer , signal (programming language) , evolutionary biology , genetics , acoustics , physics , computer science , programming language
Electron paramagnetic resonance‐based inter‐residue distance measurements between site‐directed spin‐labelled sites of sensory rhodopsin II (NpSRII) and its transducer NpHtrII from Natronobacterium pharaonis revealed a 2:2 complex with 2‐fold symmetry. The core of the complex is formed by the four transmembrane helices of a transducer dimer. Upon light excitation, the previously reported flap‐like movement of helix F of NpSRII induces a conformational change in the transmembrane domain of the transducer. The inter‐residue distance changes determined provide strong evidence for a rotary motion of the second transmembrane helix of the transducer. This helix rotation becomes uncoupled from changes in the receptor during the last step of the photocycle.