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Pontes-Buarques Mila Tessis Ana C. Bonapace José A. P. Monte Marisa B. M. Cortés-Lopez Gerardo De Souza-Barros Fernando Vieyra Adalberto 《Origins of life and evolution of the biosphere》2001,31(4-5):343-362
The adsorption of adenosine 5-monophosphate (5-AMP) ontopyrite (FeS2) and its modulation by acetate, an organic precursor of complex metabolic pathways, was studied in aqueousmedia that simulate primitive environments. 5-AMP adsorptionrequires divalent cations, indicating that a cationic bridge mediates its attachment to negatively charged sites of the mineral surface. The isotherm of 5-AMP adsorption exhibits a strong cooperative effect at low nucleotide concentrations inacetate-rich medium, whereas high levels of adsorption were only found at high nucleotide concentrations in a model of primitive seawater (acetate free). The modulating role of acetate is also evidenced in the presence of high dipolar moment molecules: dimethyl sulfoxide (Me2SO) and dimethylformamide (DMF) strongly inhibit 5-AMP adsorption in acetate-rich media, whereas no effect of DMF was found in artificial seawater. The observation that exogenous divalentcations are not needed for acetate attachment onto FeS2 reveals that organic acids can interact with the Fe2+ atoms in the mineral surface. All considered, the results showthat complex and flexible iron-sulfide/biomonomers interactionscan be modulated by molecules that accumulate in the interfacelayer. 相似文献
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