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PubMed · 9781695

Escherichia coli SecA shape and dimensions.

B Shilton·D I Svergun·V V Volkov·M H Koch·S Cusack·A Economou
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Abstract

SecA shape and conformational flexibility in solution were studied by small angle X-ray scattering. Dimeric SecA is a very elongated molecule, 15 nm long and 8 nm wide. SecA is therefore four times as long as the membrane is wide. The two globular protomers are distinctly separated and share limited surface of intermolecular contacts. ATP, ADP or adenylyl-imidodiphosphate (AMP-PNP) binding does not alter the SecA radius of gyration. A SecA mutant that catalyzes multiple rounds of ATP hydrolysis does not undergo conformational changes detectable by small angle X-ray scattering (SAXS). We conclude that SecA conformational alterations observed biochemically during nucleotide interaction are only small-scale and localized. The ramifications of these findings on SecA/SecYEG interaction are discussed.

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Adenosine DiphosphateAdenosine TriphosphatasesAdenosine TriphosphateAdenylyl ImidodiphosphateBacterial ProteinsCell MembraneDimerizationEscherichia coliEscherichia coli ProteinsMembrane Transport ProteinsModels, MolecularProtein ConformationRecombinant ProteinsSEC Translocation ChannelsScattering, RadiationSecA ProteinsSolutionsX-Ray DiffractionX-RaysJournal ArticleResearch Support, Non-U.S. Gov't

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B Shilton, D I Svergun, V V Volkov, M H Koch, S Cusack, A Economou. 1998-10-02. Escherichia coli SecA shape and dimensions.. https://doi.org/10.1016/s0014-5793(98)01141-7

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