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Chou-Fasman conformational amino acid parameters and the genetic code
I Z Siemion1, P J Siemion, K Krajewski
1Institute of Chemistry, Wroclaw University, Poland.
Bio Systems
|January 1, 1995
Summary
The genetic code's Chou-Fasman P alpha parameters follow a trigonometric function related to mutational angles. This reveals an eight-codon periodicity, except for proline, suggesting evolutionary links to ornithine.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- The Chou-Fasman P alpha conformational parameters are crucial for predicting protein secondary structures.
- Understanding the organization of the genetic code and its evolutionary history is fundamental to molecular biology.
Purpose of the Study:
- To investigate the relationship between Chou-Fasman P alpha conformational parameters and the genetic code's mutational pathways.
- To identify periodicities within the genetic code and their correlation with amino acid properties.
Main Methods:
- Analysis of Chou-Fasman P alpha values for all codons.
- Mathematical modeling using trigonometric functions to describe parameter distribution.
- Examination of codon sequences and base changes within a one-step mutation ring model.
Main Results:
- A trigonometric function accurately describes P alpha parameter distribution based on mutational angle.
- An eight-codon periodicity in P alpha values was identified, linked to regular changes in the third codon base.
- Experimental P alpha values generally fit the model, with proline as a notable exception, and suggest a potential evolutionary role for arginine codons in coding ornithine.
Conclusions:
- The genetic code exhibits a fundamental eight-codon periodicity in P alpha parameters, modulated by other periodicities.
- The observed periodicity is explained by regular third base codon changes.
- Proline's deviation and the analysis of arginine codons suggest insights into the early evolution of the genetic code.