The Distributions of Amino Acid Compositions of Proteins in an Organism's Proteome Uniformly Approximate Binomial Distributions

Abstract

Advances in the life science technologies have made it possible to access the genomic information of organisms, providing a bird's eye view of the "proteome," the entire set of proteins encoded by each genome. There have been many reports and discoveries in this research field. However, the shape of the distribution of the amino acid composition of the proteins in each proteome has not been reported.

In this study, I used NCBI proteome data. I calculated the amino acid compositions from the downloaded protein amino acid sequences. Then, I examined their distributions within each species and found that they all have bell-shaped distributions without exception.

Assuming that binomial distributions could explain these distribution shapes, I compared these proteome distributions with their adjusted binomial distributions, adjusted for lengths and means. These pairs of distributions were in fairly good agreement.

From these results, I speculated that the amino acid compositions of the proteins in each organism's proteome are in a state of mutual convergence with the amino acid compositions of the organism's cell bodies, which are composed of the proteome proteins, and this is the reason why their proteome distributions approximate binomial distributions.