A GENOMIC AND FUNCTIONAL APPRAISAL OF TWINARGININE TRANSLOCATION SYSTEM IN INTRACELLULAR BACTERIA

NUÑEZ P.; MORETTA R.; SORIA M.; FARBER M.

Carlos Paz, Córdoba

Congreso; XLIV Reunión anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular (SAIB)

The TAT system is a novel protein transport complex that targetfolded proteins across the inner membrane of Gram negativebacteria. Tat membrane components, tatA, B, and C have beenidentified in most of the bacterial sequenced genomes. However theextent to which this secretory pathway is utilized is not wellcharacterized. Comparative genomic analysis throughoutalphaproteobacteria confirmed the presence of tatA, B, and C inalmost all studied genomes. Synteny analyses allow us to split theclass in two groups with either operon or scattered organization.qRT-PCR assays using A. marginale and B. abortus RNA wereperformed to confirmed expression and determine thestoichiometric ratio of tatABC mRNA so as to characterizetranscriptional regulation mechanism. The ability of tatABC genesto compensate for the absence of the cognate E. coli one wasattained. Furthermore, a genome wide identification of putative tatsubstrates among alphaproteobacteria was performed usingTatFIND1.4. Since some organisms appear to make extensive use ofthis pathway, others seem to secrete very few products through it.GO terms and clustering analysis led to the classification of theorganism into groups regarding to the properties and number ofpredicted substrates. Whether or not this classification could be inaccordance to adaptive mechanism for very different ecologicalniches will be discussed.