Editor's Summary
3 July 2008
Origins of life: The first cell membranes
The phospholipids that form the membranes of modern cells present a formidable barrier to polar and charged molecules, necessitating complex channels and pumps to permit the exchange of molecules with the external environment. This presents a problem when trying to imagine what a primitive cell would have looked like earlier in the evolution of life. With no transport machinery, how could simple cells take in complex nutrients? A possible answer comes in the form of a model 'protocell' produced by a team at Harvard. Fatty acids and their derivatives are attractive candidates as components of early protocell membranes as they are simple amphiphiles that form bilayer membrane vesicles. A proto-cell equipped with such a membrane is found to be able to take in charged molecules such as nucleotides, while retaining longer genetic polymers made from them inside.
News and Views: Origins of life: How leaky were primitive cells?
If the first cells were simple vesicles, how did nutrients cross their membranes without help from transport proteins? A model of a primitive cell suggests that early membranes were surprisingly permeable.
David W. Deamer
doi:10.1038/454037a
Letter: Template-directed synthesis of a genetic polymer in a model protocell
Sheref S. Mansy, Jason P. Schrum, Mathangi Krishnamurthy, Sylvia Tobé, Douglas A. Treco & Jack W. Szostak
doi:10.1038/nature07018
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