PMID:21518907
| Citation |
Bonardi, F, Halza, E, Walko, M, Du Plessis, F, Nouwen, N, Feringa, BL and Driessen, AJ (2011) Probing the SecYEG translocation pore size with preproteins conjugated with sizable rigid spherical molecules. Proc. Natl. Acad. Sci. U.S.A. 108:7775-80 |
|---|---|
| Abstract |
Protein translocation in Escherichia coli is mediated by the translocase that in its minimal form consists of the protein-conducting channel SecYEG, and the motor protein, SecA. SecYEG forms a narrow pore in the membrane that allows passage of unfolded proteins only. Molecular dynamics simulations suggest that the maximal width of the central pore of SecYEG is limited to . To access the functional size of the SecYEG pore, the precursor of outer membrane protein A was modified with rigid spherical tetraarylmethane derivatives of different diameters at a unique cysteine residue. SecYEG allowed the unrestricted passage of the precursor of outer membrane protein A conjugates carrying tetraarylmethanes with diameters up to , whereas a sized molecule blocked the translocation pore. Translocation of the protein-organic molecule hybrids was strictly proton motive force-dependent and occurred at a single pore. With an average diameter of an unfolded polypeptide chain of , the pore accommodates structures of at least , which is vastly larger than the predicted maximal width of a single pore by molecular dynamics simulations. |
| Links |
PubMed PMC3093497 Online version:10.1073/pnas.1101705108 |
| Keywords |
Adenosine Triphosphatases/chemistry; Adenosine Triphosphatases/metabolism; Bacterial Proteins/chemistry; Bacterial Proteins/metabolism; Escherichia coli/metabolism; Escherichia coli Proteins/chemistry; Escherichia coli Proteins/metabolism; Membrane Transport Proteins/chemistry; Membrane Transport Proteins/metabolism; Models, Molecular; Molecular Dynamics Simulation; Molecular Structure; Protein Conformation; Protein Precursors/chemistry; Protein Precursors/metabolism; Protein Transport; Proton-Motive Force |
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