What drives the translocation of proteins?
We propose that protein translocation across membranes is driven by biased random thermal motion. This "Brownian ratchet" mechanism depends on chemical asymmetries between the cis and trans sides of the membrane. Several mechanisms could contribute to rectifying the thermal motion of the protein, such as binding and dissociation of chaperonins to the translocating chain, chain coiling induced by pH and/or ionic gradients, glycosylation, and disulfide bond formation. This helps explain the robustness and promiscuity of these transport systems.
Howard Hughes Medical Institute, Rockefeller University, New York, NY 10021.
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Simon
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Peskin
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Oster
D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism*; D018833:Chaperonins; D008962:Models, Theoretical; D009038:Motion; D011506:Proteins / Q000378:metabolism*; D013816:Thermodynamics
D011506:Proteins; D018833:Chaperonins