Journal Article

PreJuSER-5168

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Sensory rhodopsin II/transducer complex formation in detergent and in lipid bilayers studied with FRET

Kriegsmann, J.FZJ* ; Brehs, M.FZJ* ; Klare, J. P. ; Engelhard, M. ; Fitter, J.FZJ*

2009
Elsevier Amsterdam

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Please use a persistent id in citations: doi:10.1016/j.bbamem.2008.11.011

Abstract: The photophobic receptor from Natronomonas pharaonis (NpSRII) forms a photo-signalling complex with its cognate transducer (NpHtrII). In order to elucidate the complex formation in more detail, we have studied the intermolecular binding of both constituents (NpSRII and NpHtrII157; truncated at residue 157) in detergent buffers, and in lipid bilayers using FRET. The data for hetero-dimer formation of NpSRII/NpHtrII in detergent agrees well with KD values (approximately 200 nM) described in the literature. In lipid bilayers, the binding affinity between proteins in the NpSRII/NpHtrII complex is at least one order of magnitude stronger. In detergent the strength of binding is similar for both homo-dimers (NpSRII/NpSRII and NpHtrII/NpHtrII) but significantly weaker (KD approximately 16 microM) when compared to the hetero-dimer. The intermolecular binding is again considerably stronger in lipid bilayers; however, it is not as strong as that observed for the hetero-dimer. At a molar transducer/lipid ratio of 1:2000, which is still well above physiological concentrations, only 40% homo-dimers are formed. Apparently, in cell membranes the formation of the assumed functionally active oligomeric 2:2 complex depends on the full-length transducer including the helical cytoplasmic part, which is thought to tighten the transducer-dimer association.

Keyword(s): Archaeal Proteins: chemistry (MeSH) ; Archaeal Proteins: genetics (MeSH) ; Archaeal Proteins: metabolism (MeSH) ; Biophysical Phenomena (MeSH) ; Detergents (MeSH) ; Halobacteriaceae: chemistry (MeSH) ; Halobacteriaceae: genetics (MeSH) ; Halobacteriaceae: metabolism (MeSH) ; Lipid Bilayers: chemistry (MeSH) ; Models, Molecular (MeSH) ; Protein Binding (MeSH) ; Protein Multimerization (MeSH) ; Protein Structure, Quaternary (MeSH) ; Sensory Rhodopsins: chemistry (MeSH) ; Sensory Rhodopsins: genetics (MeSH) ; Sensory Rhodopsins: metabolism (MeSH) ; Signal Transduction (MeSH) ; Spectrophotometry (MeSH) ; Archaeal Proteins ; Detergents ; HtrII protein, Natronobacterium pharaonis ; Lipid Bilayers ; Sensory Rhodopsins ; J ; Fluorescence spectroscopy (auto) ; Lipid vesicle (auto) ; Photo signalling (auto) ; Sensory rhodopsin (auto) ; Membrane protein interaction (auto) ; Dissociation constant (auto)

Note: J. F. thanks G. Buldt (Forschungszentrum Julich) for continuous and sustainable support in his institute. This work was supported by the Deutsche Forschungsgerneinschaft (M.E.) and by a priority program SPP 1128 of Deutsche Forschungsgerneinschaft (FI 841/3-1,2 to J.F.). We are indebted to R. Schlesinger for providing us with bacteriorhodopsin and to R. Batra-Safferling for the discussions and comments on the manuscript.

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Contributing Institute(s):

1. Molekulare Biophysik (ISB-2)

Research Program(s):

1. Programm Biosoft (N03)

Appears in the scientific report 2009

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