IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
The LOV domain from Brucella LOV-HK: The role of the C-terminal helical flanking region in the light-to-signal propagation
Autor/es:
MARIANA GALLO, JIMENA RINALDI, MARTIN ARAN, SEBASTIÁN KLINKE, GASTÓN PARIS, DANIEL O. CICERO, FERNANDO GOLDBAUM
Lugar:
Frauenchiemsee
Reunión:
Congreso; 35th FGMR Discussion Meeting & Joint Conference of the German, Italian and Slovenian Magnetic Resonance Societies; 2013
Institución organizadora:
German, Italian and Slovenian Magnetic Resonance Societies
Resumen:
LOV domains are blue-light-activated signaling modules present in a wide range ofsensory proteins. Light modulates the virulence of the bacteria Brucella abortusthrough a LOV-histidine kinase (LOV-HK). The Brucella LOV domain adopts the α/βPAS domain fold and dimerizes through the hydrophobic β-scaffold, which appearsas a key element in the light activation [1]. According to secondary structure predictions,Brucella LOV-HK harbors a C-terminal helix (Jα) contiguous to the LOV corethat is estimated to be 34 residues long with no sequence similarity to other knownLOV proteins. To explore the functional importance of the Jα helix and to gain insightinto the Brucella LOV-HK light activation mechanism, we performed structural studieswith a stable construct consisting of the LOV core and the 37 C-terminal residues(LOVJα). We found that LOVJα, as the LOV core, is dimeric in solution and slowlyreturns to the dark state after being illuminated. The Jα helix is shorter than predicted,followed by an unstructured region to the C-terminus. The Jα helix is flexible andexposed to solvent. Its conformation does not change upon illumination. These resultssuggest that the Jα helix in the LOVJα construct is not participating in the signaltransduction, though the situation may be different in the full-length protein. The implicationsof these results in the context of others LOVJα proteins are discussed