Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR.

Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR. Research Abstract Details 

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Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR. Abstract Text:

Oleg Y Dmitriev,Karen H Freedman,Joseph Hermolin,Robert H Fillingame,

Subunit a in the membrane traversing F(0) sector of Escherichia coli ATP synthase is known to fold with five transmembrane helices (TMHs) with residue 218 in TMH IV packing close to residue 248 in TMH V. In this study, we have introduced a spin label probe at Cys residues substituted at positions 222 or 223 and measured the effects on the Trp varepsilonNH indole NMR signals of the seven Trp residues in the protein. The protein was purified and NMR experiments were carried out in a chloroform-methanol-H(2)O (4:4:1) solvent mixture. The spin label at positions 222 or 223 proved to broaden the signals of W231, W232, W235 and W241 located at the periplasmic ends of TMH IV and TMH V and the connecting loop between these helices. The broadening of W241 would require that the loop residues fold back on themselves in a hairpin-like structure much like it is predicted to fold in the native membrane. Placement of the spin label probe at several other positions also proved to have broadening effects on some of these Trp residues and provided additional constraints on folding of TMH IV and TMH V. The effects of the 223 probes on backbone amide resonances of subunit a were also measured by an HNCO experiment and the results are consistent with the two helices folding back on themselves in this solvent mixture. When Cys and Trp were substituted at residues 206 and 254 at the cytoplasmic ends of TMHs IV and V respectively, the W254 resonance was not broadened by the spin label at position 206. We conclude that the helices fold back on themselves in this solvent system and then pack at an angle such that the cytoplasmic ends of the polypeptide backbone are significantly displaced from each other.

Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR. Publishing Authors By Initials

OY Dmitriev,KH Freedman,J Hermolin,RH Fillingame,

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Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR. Journal Published:

PUBLICATION TYPE: Journal Article

Journal: Biochimica et biophysica acta

VOLUME: 1777

Page Numbers: 227-37

Journal Abbreviation: Biochim. Biophys. Acta

ISSN: 0006-3002

DAY: 15

MONTH: 12

YEAR: 2007

Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR. Information

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LANGUAGE: eng

NlmUniqueID: 217513

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Grant and Affiliation Information for Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR.

AFFILIATION: Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA.

Country: Netherlands

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MEDLINETA: Biochim Biophys Acta

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Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR Related Publications

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• Interaction of transmembrane helices in ATP synthase subunit a in solution as revealed by spin label difference NMR.
• Subunit a Facilitates Aqueous Access to a Membrane-embedded Region of Subunit c in Escherichia coli F1F0 ATP Synthase.
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• The rigid connecting loop stabilizes hairpin folding of the two helices of the ATP synthase subunit c.