Thermal unfolding of the cytotoxin alpha-sarcin: phospholipid binding induces destabilization of the protein structure.
Biochim Biophys Acta
; 1252(1): 126-34, 1995 Sep 27.
Article
em En
| MEDLINE
| ID: mdl-7548154
ABSTRACT
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.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfolipídeos
/
Conformação Proteica
/
Proteínas Fúngicas
/
Inibidores da Síntese de Proteínas
/
Endorribonucleases
/
Antineoplásicos
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
Espanha