Monte Carlo simulations of voltage-driven translocation of a signal sequence.
Transmembrane potentials play important but poorly understood roles in many biological processes, including signal sequence-mediated protein translocation across bacterial membranes. In this study we applied Monte Carlo techniques to simulate the way the potential acts on a signal sequence. The simulations demonstrate that in the absence of a potential the signal sequence prefers insertion in both helical hairpin and transmembrane alpha-helical conformations. However, in the presence of a potential only the transmembrane alpha-helical conformation is the state of lowest energy for the signal sequence. From these results it is concluded that the membrane potential stabilizes the transmembrane orientation of a signal sequence, explaining the membrane potential dependence of preprotein translocation.
M.M. Shemyakin and Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ul. Miklukho-Maklaya, 16/10, Moscow V-437, 117997 GSP, Russia. efremov@nmr.ru
Roman G
RG
Efremov
Pavel E
PE
Volynsky
Dmitry E
DE
Nolde
Annemieke
A
van Dalen
Ben
B
de Kruijff
Alexander S
AS
Arseniev
D000595:Amino Acid Sequence; D003198:Computer Simulation; D008564:Membrane Potentials / Q000502:physiology*; D008969:Molecular Sequence Data; D009010:Monte Carlo Method; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D021381:Protein Transport; D011506:Proteins / Q000378:metabolism*; D013816:Thermodynamics
D010455:Peptides; D011506:Proteins