%0 Conference Proceedings %A Grigoroudis, Asterios I.%A %A Panagiotidis, Christos A.%A %A Pilalis, Eleftherios%A %A Chatziioannou, Aristotelis%A %A Kolisis, Fragiskos N.‏%A %A Papadopoulos, Georgios%A %A Kyriakidis, D.A. %D 2009 %T Identification of additional Escherichia coli AtoC binding target elements gives new insight to bacterial regulatory networks: molecular modeling of AtoC-DNA binding domain amino acids %@ 0939-4451 %R 10.1007/s00726-009-0320-1 %I Springer %U https://hdl.handle.net/10442/8342 %X Bacterial environmental adaptation is mediated by networks of crosstalk between two component systems, while signal transduction takes place via phosphor-transfer from sensor histidine kinases to aspartic residues of response regulators, the signal output carriers. Transcriptome and phenotypic analyses indicated the involvement of the AtoSC two component system of E. coli in various cellular activities, apart from the activation of the atoDAEB operon expression, upon acetoacetate induction. The activated response regulator AtoC is reported to act as transcriptional activator and its cis-regulatory binding site was identified as a palindromic repeat within the atoDAEB promoter. The nature of the bonds formed between theAtoCamino acids and the specific DNA residues was investigated with molecular modeling. Moreover, in an attempt to define novel AtoC binding elements which would indicate an AtoC-related cross-regulatory function, we employed an ab initio motif detection approach, coupled with gene ontology analysis. The genome-wide computational screening indicated several putative matching sites within the E. coli genome. Chromatin Immunoprecipitation assayswere carried out to assess the in vivo binding ofAtoC to the predicted sites. This process verified twenty-one additional AtoC binding sites, albeit their sequence divergence, located not only within intergenic, but also within gene-encoding regions. The elucidation of the molecular conditions governing the AtoC binding to these sites in vitro and in vivo, its dimerization and putative participation of other factor(s) gives an insight to a possible AtoC-related regulatory network which may contribute to the pleiotropic effects of AtoC. %> Αποθετήριο Ήλιος / ΕΙΕ