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Computer Modeling of the Earliest Cellular Structures and FunctionsIn the absence of extinct or extant record of protocells (the earliest ancestors of contemporary cells). the most direct way to test our understanding of the origin of cellular life is to construct laboratory models of protocells. Such efforts are currently underway in the NASA Astrobiology Program. They are accompanied by computational studies aimed at explaining self-organization of simple molecules into ordered structures and developing designs for molecules that perform proto-cellular functions. Many of these functions, such as import of nutrients, capture and storage of energy. and response to changes in the environment are carried out by proteins bound to membrane< We will discuss a series of large-scale, molecular-level computer simulations which demonstrate (a) how small proteins (peptides) organize themselves into ordered structures at water-membrane interfaces and insert into membranes, (b) how these peptides aggregate to form membrane-spanning structures (eg. channels), and (c) by what mechanisms such aggregates perform essential proto-cellular functions, such as proton transport of protons across cell walls, a key step in cellular bioenergetics. The simulations were performed using the molecular dynamics method, in which Newton's equations of motion for each item in the system are solved iteratively. The problems of interest required simulations on multi-nanosecond time scales, which corresponded to 10(exp 6)-10(exp 8) time steps.
Document ID
20040084428
Document Type
Conference Paper
Authors
Pohorille, Andrew (NASA Ames Research Center Moffett Field, CA, United States)
Chipot, Christophe (NASA Ames Research Center Moffett Field, CA, United States)
Schweighofer, Karl (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 21, 2013
Publication Date
March 1, 2000
Subject Category
Exobiology
Meeting Information
American Physical Society Meeting(Minneapolis, MN)
Funding Number(s)
PROJECT: RTOP 344-50-92-02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.