Goepfert, Arnaud. Fic-mediated adenylylation : catalysis and regulation. 2014, PhD Thesis, University of Basel, Faculty of Science.
Official URL: http://edoc.unibas.ch/diss/DissB_10796
The FIC domain is not only present in a pathogenic setting but is also found in proteins that play a role in intrinsic signaling processes where its deleterious adenylylation activity needs to be tightly regulated.
In this study, I performed structural and biochemical analyses to unravel the structural determinants and mechanisms governing catalysis and regulation of Fic proteins as widespread signaling proteins.
First, by solving various structures of FIC domain-containing proteins I could show that FIC utilizes conserved active site features to favorably orientate the ATP substrate relative to the target protein, allowing AMP transfer to occur. We suggest that the catalytic mechanism can be generalized and extrapolated to all adenylylation-competent Fic proteins.
Second, I deciphered the structural mechanism controlling Fic-catalyzed adenylylation. An alpha helix characterized by a conserved [S/T]xxxE[G/N] motif tightly associates with the Fic active site and perturbs adenylylation-competent ATP binding. This alpha helix can be part of the Fic protein itself as an N- or a C-terminal extension, or can be provided by a separate antitoxin. Based on structural homology modeling, this regulation mechanism was found to be conserved from bacteria to higher eukaryotes.
The structural insights on the protein-ATP substrate binding specificity accumulated in this study will prove useful for coming efforts on rational drug design. Furtheremore, knowledge of the universal catalytic and inhibitory mechanism of Fic mediated AMP transfer will now pave the way for further studies towards the physiological roles of Fic proteins and particularly the identification of their protein targets.
|Committee Members:||Dehio, Christoph|
|Faculties and Departments:||05 Faculty of Science > Departement Biozentrum > Structural Biology & Biophysics > Structural Biology (Schirmer)|
|Bibsysno:||Link to catalogue|
|Number of Pages:||166 S.|
|Last Modified:||30 Jun 2016 10:55|
|Deposited On:||16 Jun 2014 06:52|
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