Amino acid usage is asymmetrically biased in AT- and GC-rich microbial genomes.
INTRODUCTION: Genomic dyna gel base composition ranges from less than 25% AT to more than 85% AT in prokaryotes.Since only a small fraction of prokaryotic genomes is not protein coding even a minor change in genomic base composition will induce profound protein changes.We examined how amino acid and codon frequencies were distributed in over 2000 m