The effect of membrane binding on the structure and stability of the cytotoxin alpha-sarcin has been studied by differential scanning calorimetry, Fourier-transform infrared and fluorescence spectroscopic techniques. The thermal unfolding of alpha-sarcin in aqueous solution fits into a two-state transition characterized by a transition temperature (Tm) of 52.6 degrees C and a calorimetric enthalpy (delta Hcal) of 136 kcal/mol. Upon interaction with phosphatidylglycerol vesicles, alpha-sarcin undergoes conformational changes, as deduced from the FTIR and fluorescence emission spectra. These changes result in a decreased Tm and delta Hcal values for the thermal unfolding of phospholipid-bound alpha-sarcin. The lower Tm value for lipid-bound alpha-sarcin is also observed at the level of secondary and tertiary structures, based on analyses of both the amide I' infrared spectrum and the tryptophan emission of the protein as a function of temperature, respectively. The results obtained indicate a protein destabilization promoted by the phospholipid interaction. Study holds ProTherm entries: 9370 Extra Details: additive : EDTA(1 mM), protein calorimetry; infrared spectroscopy of protein;,protein-lipid interaction; ribosome-inactivating protein
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:37 p.m.
|Number of data points||2|
|Proteins||Ribonuclease alpha-sarcin ; Ribonuclease alpha-sarcin|
|Assays/Quantities/Protocols||Experimental Assay: dHcal ; Experimental Assay: Tm|
|Libraries||Mutations for sequence AVTWTCLNDQKNPKTNKYETKRLLYNQNKAESNSHHAPLSDGKTGSSYPHWFTNGYDGDGKLPKGRTPIKFGKSDCDRPPKHSKDGNGKTDHYLLEFPTFPDGHDYKFDSKKPKENPGPARVIYTYPNKVFCGIIAHTKENQGELKLCSH|