Polypurine.polypyrimidine sequences in complete bacterial genomes: preference for polypurines in protein-coding regions

Raghavan, Sowmya and Hariharan, Ramesh and Brahmachari, Samir K (2000) Polypurine.polypyrimidine sequences in complete bacterial genomes: preference for polypurines in protein-coding regions. In: GENE, 242 (1-2). pp. 275-283.

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Abstract

The genomes of Methanococcus jannaschii, Mycoplasma genitalium, Haemophilus influenzae, Archaeoglobus fulgidus, Helicobacter pylori, Treponema pallidum, Borrelia burgdorferri, Rickettsia prowazekeii, Mycobacterium tuberculosis, Methanobacterium thermoautotrophicum, Synechocystis sp. PCC6803, Bacillus subtilis, Chlamydia trachomatis, Pyrococcus horikoshii, Aquifex aeolicus, Mycoplasma pneumoniae and Escherichia coli have been analysed for the presence of polypurine.polypyrimidine tracts, in order to understand their distribution in these genomes. We observed a variation in abundance of such sequences in these bacteria, with the archaeal genomes forming a high-abundance group and the canonical eubacteria forming a low-abundance group. The genomes of M. tuberculosis and A. aeolicus are unique among the organisms analysed here in the abnormal underrepresentation and overrepresentation of polypurine.polypyrimidine, respectively. We also observe a strand bias, i.e., a preferential occurrence of polypurines in coding strands. It varies widely among the bacteria, from the very high bias in M. jannaschii to the slightly inverse bias in the parasitic genomes of T. pallidum and C. trachomatis. The extent of strand bias, however, cannot be explained on the basis of the GC-content of the genome, use of all-purine codons or an excess in the amino acids that are encoded by such codons. The probable causes and effects of this phenomenon are discussed.

Item Type:	Journal Article
Publication:	GENE
Publisher:	Elsevier
Additional Information:	Copyright of this article belongs to Elsevier
Keywords:	Cis-regulation;Codon usage;Comparative genomics;Repeat sequence;Triplex
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit Division of Electrical Sciences > Computer Science & Automation
Date Deposited:	14 May 2009 06:30
Last Modified:	19 Sep 2010 04:51
URI:	http://eprints.iisc.ac.in/id/eprint/16238

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