Abstract
The structure of subunit a of the Escherichia coli ATP synthase has been probed by construction of more than one hundred monocysteine substitutions. Surface labeling with 3-N-maleimidyl-propionyl biocytin (MPB) has defined five transmembrane helices, the orientation of the protein in the membrane, and information about the relative exposure of the loops connecting these helices. Cross-linking studies using TFPAM-3 (N-(4-azido-2,3,5,6-tetrafluorobenzyl)-3-maleimido-propionamide) and benzophenone-4-maleimide have revealed which elements of subunit a are near subunits b and c. Use of a chemical protease reagent, 5-(-bromoacetamido)-1,10-phenanthroline-copper, has indicated that the periplasmic end of transmembrane helix 5 is near that of transmembrane helix 2.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Review
MeSH terms
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Bacterial Proton-Translocating ATPases
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Cysteine
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Escherichia coli Proteins / chemistry*
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism
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Membrane Proteins / chemistry
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Mitochondrial Proton-Translocating ATPases / chemistry*
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Mitochondrial Proton-Translocating ATPases / genetics
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Mitochondrial Proton-Translocating ATPases / metabolism
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Mutagenesis, Site-Directed
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Protein Conformation
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Protein Subunits / chemistry*
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Protein Subunits / genetics
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Protein Subunits / metabolism
Substances
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Escherichia coli Proteins
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Membrane Proteins
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Protein Subunits
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Bacterial Proton-Translocating ATPases
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Mitochondrial Proton-Translocating ATPases
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atpB protein, E coli
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Cysteine