title: Collaboration between primitive cell membranes and soluble catalysts.
abstract: One widely held model of early life suggests primitive cells consisted of simple RNA-based catalysts within lipid compartments. One possible selective advantage conferred by an encapsulated catalyst is stabilization of the compartment, resulting from catalyst-promoted synthesis of key membrane components. Here we show model protocell vesicles containing an encapsulated enzyme that promotes the synthesis of simple fatty acid derivatives become stabilized to Mg(2+), which is required for ribozyme activity and RNA synthesis. Thus, protocells capable of such catalytic transformations would have enjoyed a selective advantage over other protocells in high Mg(2+) environments. The synthetic transformation requires both the catalyst and vesicles that solubilize the water-insoluble precursor lipid. We suggest that similar modified lipids could have played a key role in early life, and that primitive lipid membranes and encapsulated catalysts, such as ribozymes, may have acted in conjunction with each other, enabling otherwise-impossible chemical transformations within primordial cells.
authors.affiliation: Howard Hughes Medical Institute and Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.
authors.forename: Katarzyna P
authors.initials: KP
authors.lastname: Adamala
authors.affiliation: Howard Hughes Medical Institute and Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.
authors.forename: Aaron E
authors.initials: AE
authors.lastname: Engelhart
authors.affiliation: Howard Hughes Medical Institute and Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.
authors.forename: Jack W
authors.initials: JW
authors.lastname: Szostak
mesh_terms: D002384:Catalysis / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002918:Chymotrypsin / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D019301:Oleic Acid / Q000378:metabolism*; D016337:RNA, Catalytic / Q000378:metabolism; D012995:Solubility
chemical_list: D016337:RNA, Catalytic; D019301:Oleic Acid; D002918:Chymotrypsin; D008274:Magnesium