Εξειδίκευση τύπου :	Περίληψη σε συνέδριο
Τίτλος:	Functional characterization of AtoS-histidine protein kinase in E-coli
Δημιουργός/Συγγραφέας:	Filippou, P. S. Kasemian, L. D. Panagiotidis, C. A. [EL] Κυριακίδης, Δ.Α.[EN] Kyriakidis, D.A.
Εκδότης:	Springer
Ημερομηνία:	2007
Γλώσσα:	Αγγλικά
ISSN:	0939-4451
DOI:	10.1007/s00726-007-0578-0
Περίληψη:	AtoS is the membrane signal-transducing histidine kinase (HK) that together with the response regulator AtoC plays a pivotal role in the transcriptional regulation of atoDAEB operon in Escherichia coli. The carboxyl-terminal cytoplasmic region of an HK called transmitter domain consists of an ATP-binding region and a so-called H-box that includes the conserved histidine residue which represents the site for self-phosphorylation. Upon acetoacetate induction the AtoS kinase autophosphorylates and subsequently transfers the phosphoryl group to AtoC thus leading to its activation. To localize AtoS autophosphorylation site chemical stability tests and site directed mutagenesis were performed. These experiments identify the histidine-398 which is located within the conserved H-box as the site of phosphorylation. In order to elucidate the mechanism of AtoS autophosphorylation cross-linking experiments with recombinant his-tagged protein AtoS and its cytosolic portion (lacking the two N-terminal transmembrane domains) were performed. Ligand-induced dimerization would be expected to cause kinase activation by shifting the equilibrium between inactive histidine kinase monomers and active dimers. Cross-linking experiments in vivo in the presence or absence of acetoacetate also demonstrated the importance of signal-binding for the dimerization or oligomerization of AtoS procedure. In addition two inactive forms of AtoS lacking the histidine autophosphorylation site and the ability of ATP binding in the G-box respectively were found to be necessary for the autophosphorylation reaction in vitro. These results indicate that the autophosphorylation reaction of AtoS occurs within the dimer by a trans-intersubunit mechanism and dimerization may be a prerequisite for trans-phosphorylation and activation of AtoS.
Τίτλος πηγής δημοσίευσης:	Amino Acids 33:3(Sept2007):XXXIX, 10th International Congress on Amino Acids and Proteins (ICAAP), Kallithea, Chalkidiki, Greece, 20 - 25 August, 2007
Ηλεκτρονική διεύθυνση περιοδικού (link) :	http://www.springer.at/amino_acids
Σημειώσεις:	Abstract
Εμφανίζεται στις συλλογές:	Άλλες δράσεις