Thu, 21 Aug 2008 07:37:19 BST CiteULike: neils Dutta http://www.citeulike.org/user/neils/author/Dutta CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/neils/article/2644009 <i>Genome Biology, Vol. 9, No. 4. (2008)</i><br /><br />BACKGROUND:Halophilic prokaryotes are adapted to thrive in extreme conditions of salinity. Identification and analysis of distinct macromolecular characteristics of halophiles provide insight into the factors responsible for their adaptation to high-salt environment. The current report presents an extensive and systematic comparative analysis of genome and proteome composition of halophilic and non-halophilic microorganisms, with a view to identify such macromolecular signatures of haloadaptation. RESULTS:Comparative analysis of genome and proteome of halophiles and non-halophiles reveal some common trends in halophiles that transcend the boundary of phylogenetic relationship and the genomic GC-content of the species. At the protein level, halophilic species are characterized by low hydrophobicity; overrepresentation of acidic residues, especially Asp; underrepresentation of Cys; lower propensities for helix formation and higher propensities for coil structure. At the DNA level, the dinucleotide abundance profiles of halophilic genomes bear some common characteristics, which are quite distinct from those of non-halophiles and hence, may be regarded as specific genomic signatures for salt-adaptation. The synonymous codon usage in halophiles also exhibit similar patterns regardless of their long-term evolutionary history. CONCLUSION:The generality of molecular signatures for environmental adaptation of extreme salt-loving organisms, demonstrated in the present study, advocates for convergent evolution of halophilic species towards specific genome and amino acid composition, irrespective of their varying GC-bias and widely disparate taxonomic positions. The adapted features of halophiles seem to be related to physical principles governing DNA and protein stability, in response to the extreme environmental conditions in which they thrive. Molecular Signature of Hypersaline Adaptation: Insights from Genome and Proteome Composition of Halophilic Prokaryotes Sandip Paul Sumit Bag Sabyasachi Das Eric Harvill Chitra Dutta doi:10.1186/gb-2008-9-4-r70 Genome Biology, Vol. 9, No. 4. (2008) 2008-04-09T08:46:48-00:00 2008 Genome Biology 9 4 adaptation bioinformatics comparative genomics halophile prokaryote proteomics