title: The probability of nonsense mutation caused by replication-associated mutational pressure is much higher for bacterial genes from lagging than from leading strands.
abstract: We studied nucleotide usage biases in 4-fold degenerated sites of all the genes from leading and lagging strands of 30 bacterial genomes. The level of guanine in 4-fold degenerated sites (G4f) is significantly lower in genes from lagging strands than in genes from leading strands, probably because of the faster rates of guanine oxidation in single-stranded DNA leading to G to T transversions. The rates of cytosine deamination causing C to T transitions are also higher in lagging strands. We showed that the level of codons able to form stop-codons by the way of G to T transversions and C to T transitions is always higher than the level of codons able to form stop-codons by the way of C to A transversions and G to A transitions. This circumstance can be an explanation of the lower percent of ORFs in lagging strands of bacterial replichores than in leading strands.
authors.affiliation: Department of General Chemistry, Belarussian State Medical University, Minsk, Dzerzinskogo, Belarus. vvkhrustalev@mail.ru
authors.forename: Vladislav Victorovich
authors.initials: VV
authors.lastname: Khrustalev
authors.forename: Eugene Victorovich
authors.initials: EV
authors.lastname: Barkovsky
mesh_terms: D001482:Base Composition / Q000235:genetics; D016000:Cluster Analysis; D003062:Codon / Q000235:genetics; D018389:Codon, Nonsense / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics / Q000502:physiology*; D004277:DNA, Single-Stranded / Q000096:biosynthesis / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics* / Q000502:physiology; D006147:Guanine / Q000378:metabolism; D010084:Oxidation-Reduction; D010802:Phylogeny
chemical_list: D003062:Codon; D018389:Codon, Nonsense; D004277:DNA, Single-Stranded; D006147:Guanine