The small heat shock proteins from Acidithiobacillus ferrooxidans: gene expression, phylogenetic analysis, and structural modeling

Autor(es)

Ribeiro, Daniela A. ^[1] ; Del Bem, Luiz E. V. ^[1] ; Vicentini, Renato ^[1] ; Ferraz, Lucio F. C. ^[1] ; Murakami, Mario T. ^[2] ; Ottoboni, Laura M. M. ^[1]

Afiliação do(s) autor(es)

^[1] State Univ Campinas UNICAMP, Ctr Mol Biol & Genet Engn CBMEG, BR-13083875 Campinas, SP - Brazil

^[2] Natl Lab Energy & Mat Res CNPEM, Natl Biosci Lab LNBio, BR-13083970 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: BMC Microbiology; v. 11, DEC 7 2011.
• Citações Web of Science: 2

Resumo

Background: Acidithiobacillus ferrooxidans is an acidophilic, chemolithoautotrophic bacterium that has been successfully used in metal bioleaching. In this study, an analysis of the A. ferrooxidans ATCC 23270 genome revealed the presence of three sHSP genes, Afe\_1009, Afe\_1437 and Afe\_2172, that encode proteins from the HSP20 family, a class of intracellular multimers that is especially important in extremophile microorganisms. Results: The expression of the sHSP genes was investigated in A. ferrooxidans cells submitted to a heat shock at 40 degrees C for 15, 30 and 60 minutes. After 60 minutes, the gene on locus Afe\_1437 was about 20-fold more highly expressed than the gene on locus Afe\_2172. Bioinformatic and phylogenetic analyses showed that the sHSPs from A. ferrooxidans are possible non-paralogous proteins, and are regulated by the sigma(32) factor, a common transcription factor of heat shock proteins. Structural studies using homology molecular modeling indicated that the proteins encoded by Afe\_1009 and Afe\_1437 have a conserved alpha-crystallin domain and share similar structural features with the sHSP from Methanococcus jannaschii, suggesting that their biological assembly involves 24 molecules and resembles a hollow spherical shell. Conclusion: We conclude that the sHSPs encoded by the Afe\_1437 and Afe\_1009 genes are more likely to act as molecular chaperones in the A. ferrooxidans heat shock response. In addition, the three sHSPs from A. ferrooxidans are not recent paralogs, and the Afe\_1437 and Afe\_1009 genes could be inherited horizontally by A. ferrooxidans. (AU)

• Processo FAPESP: 02/07642-3 - Expressao diferencial de genes em acidithiobacillus ferrooxidans submetida ao estresse induzido por ph, temperatura e privacao de fosfato.
• Beneficiário: Laura Maria Mariscal Ottoboni
• Modalidade de apoio: Auxílio à Pesquisa - Regular