title: Differential thermodynamic behaviours of the extra-cellular regions of two Ser/Thr PrkC kinases revealed by calorimetric studies.
abstract: Eukaryotic-type Ser/Thr protein-kinases are critical mediators of developmental changes and host pathogen interactions in bacteria. Although with lower abundance compared to their homologues from eukaryotes, Ser/Thr protein-kinases (STPK) are widespread in gram positive bacteria, where they regulate several cellular functions. STPKs belong to the protein kinase family named as one-component signal transduction systems, which combine both sensing and regulating properties. Thermodynamic investigations of sensing extra-cellular portions of two important Ser-Thr kinases, PrkC, from Staphylococcus aureus and Bacillus subtilis were conducted by differential scanning calorimetry (DSC) and circular dichroism (CD) melting measurements, coupled with modelling studies. The study of thermodynamic properties of the two domains is challenging since they share a modular domain organization. Consistently, DSC and CD data show that they present similar thermodynamic behaviours and that folding/unfolding transitions do not fit a two-state folding model. However, the thermal unfolding of the two proteins is differentially sensitive to pH. In particular, their unfolding is characteristic of modular structures at the neutral pH, with independent contributions of individual domains to folding. Differently, a cooperative unfolding is evidenced at acidic pH for the B. subtilis member, suggesting that a significant interaction between domains becomes valuable.
authors: Institute of Biostructures and Bioimaging, CNR, via Mezzocannone 16, Napoli, Italy. Electronic address: rita.berisio@unina.it.
authors: Rita
authors: R
authors: Berisio
authors: Institute of Biostructures and Bioimaging, CNR, via Mezzocannone 16, Napoli, Italy.
authors: Flavia
authors: F
authors: Squeglia
authors: Institute of Biostructures and Bioimaging, CNR, via Mezzocannone 16, Napoli, Italy.
authors: Alessia
authors: A
authors: Ruggiero
authors: Department of Chemical Sciences, University of Naples Federico II, via Cintia, 80126 Napoli, Italy.
authors: Luigi
authors: L
authors: Petraccone
authors: Department of Chemical Sciences, University of Naples Federico II, via Cintia, 80126 Napoli, Italy.
authors: Marco Ignazio
authors: MI
authors: Stellato
authors: Department of Chemical Sciences, University of Naples Federico II, via Cintia, 80126 Napoli, Italy. Electronic address: pompea.delvecchio@unina.it.
authors: Pompea
authors: P
authors: Del Vecchio
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000201:enzymology; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011493:Protein Kinase C / Q000737:chemistry*; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D058767:Protein Unfolding; D017386:Sequence Homology, Amino Acid; D013211:Staphylococcus aureus / Q000201:enzymology; D013816:Thermodynamics
chemical_list: D011493:Protein Kinase C
keywords: CD; DSC; Eukaryotic-type serine/threonine kinases; Thermal unfolding of multi-domain proteins