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Conformational changes in the Escherichia coli ATP synthase b-dimer upon binding to F1-ATPase |
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| Authors: | Tarek M. Zaida Tassilo Hornung Oleg A. Volkov Andrea D. Hoffman Susan J. Pandey John G. Wise Pia D. Vogel |
| Affiliation: | (1) Department of Biological Sciences, Southern Methodist University, 6501 Airline Rd., Dallas, TX 75275, USA;(2) Present address: Biomedicine and Biotechnology, School of Life Sciences, Arizona State University, Tempe, AZ, USA |
| Abstract: | Conformational changes within the subunit b-dimer of the E. coli ATP synthase occur upon binding to the F1 sector. ESR spectra of spin-labeled b at room temperature indicated a pivotal point in the b-structure at residue 62. Spectra of frozen b ± F1 and calculated interspin distances suggested that where contact between b 2 and F1 occurs (above about residue 80), the structure of the dimer changes minimally. Between b-residues 33 and 64 inter-subunit distances in the F1-bound b-dimer were found to be too large to accommodate tightly coiled coil packing and therefore suggest a dissociation and disengagement of the dimer upon F1-binding. Mechanistic implications of this “bubble” formation in the tether domain of ATP synthase b 2 are discussed. This work was supported by grant from the National Science Foundation (MCB 0415713) to PDV |
| Keywords: | Coiled coil ESR Spin-labeling ATPase Conformational changes b-dimer External stalk |
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