Thermal unfolding of calreticulin. Structural and thermodynamic characterization of the transition

BORIOLI GRACIELA

BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2019 vol. 1867 p. 175 - 175

0005-2736

alreticulin (CRT) is a calcium-binding protein thatparticipates in several cellular processes including the control ofprotein folding and homeostasis of Ca2+. Its folding, stability andfunctions are strongly controlled by the presence of Ca2+. Theoligomerization state of CRT is also relevant for its functions. Westudied the thermal transitions of monomers and oligomers of CRT bydifferential scanning calorimetry (DSC), circular dichroism (CD) andFourier transform infrared spectroscopy (FTIR) in the presence andabsence of Ca2+. We found three and two components for the calorimetrictransition in the presence and absence of Ca2+ respectively. The presenceof several components was also supported by CD and FTIR spectra acquiredas a function of the temperature. The difference between the heatcapacity of the native and the unfolded state strongly suggests thatinteractions between protein domains also contribute to the heat uptakein a calorimetry experiment. We found that once unfolded at high