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Selective adsorption of l- and d-amino acids on calcite: Implications for biochemical homochirality

By Robert M. Hazen, Timothy R. Filley and Glenn A. Goodfriend

Abstract

The emergence of biochemical homochirality was a key step in the origin of life, yet prebiotic mechanisms for chiral separation are not well constrained. Here we demonstrate a geochemically plausible scenario for chiral separation of amino acids by adsorption on mineral surfaces. Crystals of the common rock-forming mineral calcite (CaCO3), when immersed in a racemic aspartic acid solution, display significant adsorption and chiral selectivity of d- and l-enantiomers on pairs of mirror-related crystal-growth surfaces. This selective adsorption is greater on crystals with terraced surface textures, which indicates that d- and l-aspartic acid concentrate along step-like linear growth features. Thus, selective adsorption of linear arrays of d- and l-amino acids on calcite, with subsequent condensation polymerization, represents a plausible geochemical mechanism for the production of homochiral polypeptides on the prebiotic Earth

Topics: Physical Sciences
Publisher: The National Academy of Sciences
Year: 2001
DOI identifier: 10.1073/pnas.101085998
OAI identifier: oai:pubmedcentral.nih.gov:33239
Provided by: PubMed Central
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