ORGN 286 |
| Chi Ming Yang, Neurochemistry and Physical Organic Chemistry, Neurochemistry and Physical Organic Chemistry, Nankai University, Tianjin, 300071, China |
| To explore how chemical structures of both nucleobases and amino acids may have played a role in shaping the genetic code, numbers of sp2 hybridized nitrogen atoms in nucleobases were taken as a determinative measure for empirical stereo-electronic property to analyze the genetic code. Results revealed that amino acid hydropathy correlates strongly with the sp2 nitrogen-atom numbers in nucleobases rather than with the overall electronic property such as redox potentials of the bases, reflecting that stereo-electronic property of bases may play a role. In the rearranged code, five simple but stereo-structurally distinctive amino acids (Gly, Pro, Val, Thr and Ala) and their codon quartets form a crossed intersection "core". Secondly, a re-categorizations of the amino acids according to their beta-carbon stereochemistry, verified by charge density (at beta-carbon) calculation, resulted in five groups of stereo-structurally distinctive amino acids, the group leaders of which are Gly, Pro, Val, Thr and Ala, remarkably overlapping the above "core". These two lines of independent observations provide empirical arguments for a contention that a seemingly "frozen core" could have formed at a certain evolutionary stage. The possible existence of this codon "core" is in conformity with a previous evolutionary model whereby stereochemical interactions may have shaped the code. Moreover, the genetic code listed in UCGA succession together with this codon "core" has recently facilitated an identification of the unprecedented icosikaioctagon symmetry and bi-pyramidal nature of the genetic code. |
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Physical Organic, Combinatorial, Materials, Molecular Recognition
8:00 PM-10:00 PM, Tuesday, March 30, 2004 Anaheim Convention Center -- Hall A, Poster
Sci-Mix
Division of Organic Chemistry |