Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle.

Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle. Research Abstract Details 

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Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle. Abstract Text:

Brian E Schwem,Robert H Fillingame,

Subunit a of F(1)F(0) ATP synthase is required in the H(+) transport driven rotation of the c-ring of F(0), the rotation of which is coupled to ATP synthesis in F(1). The three-dimensional structure of subunit a is unknown. In this study, Cys substitutions were introduced into two different transmembrane helices (TMHs) of subunit a, and the proximity of the thiol side chains was tested via attempted oxidative cross-linking to form the disulfide bond. Pairs of Cys substitutions were made in TMHs 2/3, 2/4, 2/5, 3/4, 3/5, and 4/5. Cu(+2)-catalyzed oxidation led to cross-link formation between Cys pairs L120C(TMH2) and S144C(TMH3), L120C(TMH2) and G218C(TMH4), L120C(TMH2) and H245C(TMH5), L120C(TMH2) and I246C(TMH5), N148C(TMH3) and E219C(TMH4), N148C(TMH3) and H245C(TMH5), and G218C(TMH4) and I248C(TMH5). Iodine, but not Cu(+2), was found to catalyze cross-link formation between D119C(TMH2) and G218C(TMH4). The results suggest that TMHs 2, 3, 4, and 5 form a four-helix bundle with one set of key functional residues in TMH4 (Ser-206, Arg-210, and Asn-214) located at the periphery facing subunit c. Other key residues in TMHs 2, 4, and 5, which were concluded previously to compose a possible aqueous access pathway from the periplasm, were found to locate to the inside of the four-helix bundle.

Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle. Publishing Authors By Initials

BE Schwem,RH Fillingame,

For similar proteins: protein subunits research abstracts see: proteins: protein subunits research

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Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle. Journal Published:

PUBLICATION TYPE: Research Support, N.I.H., Extr

Journal: The Journal of biological chemistry

VOLUME: 281

Page Numbers: 37861-7

Journal Abbreviation: J. Biol. Chem.

ISSN: 0021-9258

DAY: 11

MONTH: 10

YEAR: 2006

Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle. Information

Number of References:

LANGUAGE: eng

NlmUniqueID: 2985121

Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle. Keywords Mesh Terms:

KEYWORDS: Protein Subunits

MESH TERMS: genetics

Chemical & Substance for Abstract: Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle. Information

Substance Name: Bacterial Proton-Translocating ATPases

Registry Number: EC 3.6.1.-

Grant and Affiliation Information for Cross-linking between helices within subunit a of Escherichia coli ATP synthase defines the transmembrane packing of a four-helix bundle.

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

Country: United States

AGENCY: United States NIGMS

GRANT: GM23105

ACRONYM: GM

MEDLINETA: J Biol Chem

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