S., Zaia C.T. B. V., Zaia D. A. M. (2007). Amino acid interaction with and adsorption on clays: VX-680 cell line FT-IR and Mössbauer spectroscopy and X-ray diffractometry investigations. Orig. Life Evol. Biosph. 37: 479–493. Bernal J. D. (1951). The physical basis of life. SBE-��-CD Routledge and Kegan Paul, London. Lambert J. F. (2008). Adsorption and Polymerization of Amino Acids on Mineral Surfaces: A Review. Orig. Life Evol. Biosph. DOI 10.1007/s11084–008–9128–3 Zaia D. A. M. (2004). A review
of adsorption of amino acids on minerals: was it important for origin of life? Amino Acids 27: 113–118. Zaia D. A. M., Vieira H. J., Zaia C. T. B. V. (2002). Adsorption of L-amino acids on sea sand. J. Braz. Chem. Soc. 13: 679–681. E-mail: [email protected]br Origins of Genetic Information A Primitive RNA Transition Scenario Without Cytosine and with Peptides Interacting with RNA: Implications for the Origin of the Genetic Code 1Delaye L., 1Becerra A., 2Martinez-Mekler G., 3Cocho G. 1Laboratorio de Microbiología, Facultad de Ciencias, this website UNAM, Mexico D.F. 04510, Mexico; 2Centro de Física, UNAM,
Cuernavaca, 62251, Mexico; 3Instituto de Física, UNAM, Mexico D.F. 01000, Mexico We propose a primitive RNA transition scenario without cytosine and with peptides interacting with RNA. We consider riboproteins as representative of these primitive peptides and compute these amino acid frequencies. The more frequent amino acids found are: Lys, Ala, Val, Arg, Leu, Gly, Ile and Glu. In addition to glycine, amino acids with helix propensities dominate. These more frequent amino acids can be coded by uracyl, adenine and guanine, without cytocine, and by NNR codons. The analysis suggest a primitive genetic code with RRR for polar amino acids (gly, glu,
lys and arg) and YYR, YRR and RYR for non polar ones and stop codons. Later, with cytosine arrival serine, proline, threonine and glutamine would be coded by NNR codons containing cytosine, and perhaps much later, NNY codons would be occupied by additional low frequency amino acids. Previous, old, amino Grape seed extract acids would also occupy the new NNY codons. E-mail: [email protected]unam.mx Amino Acid Homochirality Based on the Origin of Phosphate-Based Life Daxiong Han1, Haiyan Wang 2, Yufen Zhao1,3 1Department of Pharmacy, Medical College of Xiamen University, Xiamen, China; 2Third Institute of Oceanography, State Oceanic Administration of China, Xiamen, China; 3The Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China The emergence of phosphorylation has to have been one of the key events in prebiotic evolution on earth. In this paper, the emergence of phosphoryl amino-acid 5′-nucleosides having a P–N bond is described as a model of the origin of amino-acid homochirality and genetic code (Figure 1).