The self-reproduction of vesicles formed by (S)- and (R)-2-methyldodecanoic acid (4) was investigated in order to relate the autocatalytic increase of the vesicle concentration with enantioselectivity. 4(R) and 4(S) were synthesized with an enantiomeric excess greater than 98%. 4 forms vesicles in aqueous solution in the pH region between 8.8 and 7.5. Chiral properties of the vesicles were studied by differential scanning calorimetry (DSC) and circular dichroism (CD). For self-reproduction studies, the hydrolysis of the water-insoluble 2-methyldodecanoic anhydride (8) was investigated in a biphasic system consisting of an aqueous solution and 8. The reaction rates of 8(RR) and 8(SS) catalyzed by 4(R) or 4(S) vesicles were the same within experimental errors, indicating that the chiral vesicles cannot induce significant enantioselectivity. However, a clear effect was observed at 10 °C: racemic vesicles destabilized during hydrolysis, causing phase separation, whereas homochiral vesicles remained stable and continued to self-reproduce.
Autopoietic self-Reproduction of chiral fatty acid vesicles / K. Morigaki, S. Dallavalle, P. Walde, S. Colonna, P.L. luisi. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - 119:2(1997), pp. 292-301. [10.1021/ja961728b]
Autopoietic self-Reproduction of chiral fatty acid vesicles
S. DallavalleSecondo
;S. ColonnaPenultimo
;
1997
Abstract
The self-reproduction of vesicles formed by (S)- and (R)-2-methyldodecanoic acid (4) was investigated in order to relate the autocatalytic increase of the vesicle concentration with enantioselectivity. 4(R) and 4(S) were synthesized with an enantiomeric excess greater than 98%. 4 forms vesicles in aqueous solution in the pH region between 8.8 and 7.5. Chiral properties of the vesicles were studied by differential scanning calorimetry (DSC) and circular dichroism (CD). For self-reproduction studies, the hydrolysis of the water-insoluble 2-methyldodecanoic anhydride (8) was investigated in a biphasic system consisting of an aqueous solution and 8. The reaction rates of 8(RR) and 8(SS) catalyzed by 4(R) or 4(S) vesicles were the same within experimental errors, indicating that the chiral vesicles cannot induce significant enantioselectivity. However, a clear effect was observed at 10 °C: racemic vesicles destabilized during hydrolysis, causing phase separation, whereas homochiral vesicles remained stable and continued to self-reproduce.
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