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Effect of temperature and pH on the structure and stability of tumor-specific lectin jacalin and insights into the location of its tryptophan residues: CD, DSC and fluorescence studies.
Banerjee, Sneha; Naresh, Madarapu; Swamy, Musti J.
Afiliação
  • Banerjee S; School of Chemistry, University of Hyderabad, Hyderabad 500 046, India.
  • Naresh M; Polymers and Functional Materials Division, CSIR - Indian Institute of Chemical Technology, Hyderabad 500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India.
  • Swamy MJ; School of Chemistry, University of Hyderabad, Hyderabad 500 046, India. Electronic address: mjswamy@uohyd.ac.in.
Int J Biol Macromol ; 260(Pt 2): 129451, 2024 Mar.
Article em En | MEDLINE | ID: mdl-38232886
ABSTRACT
Jacalin, the jackfruit seed lectin, exhibits high specificity for the tumor-specific T-antigen and is used in various biomedical and biotechnological applications. Here, we report biophysical studies on the thermal unfolding of jacalin and the effect of pH and temperature on its secondary structure. Differential scanning calorimetric (DSC) studies revealed that native jacalin unfolds at ∼60 °C and that carbohydrate binding stabilizes the protein structure. Circular dichroism spectroscopic studies indicated that the secondary structure of jacalin remains mostly unaffected over pH 2.0-9.0, whereas considerable changes were observed in the tertiary structure. DSC experiments demonstrated that jacalin exhibits two overlapping transitions between pH 2 and 5, which could be attributed to dissociation of the tetrameric protein into subunits and their unfolding. Interestingly, only one transition between pH 6 and 9 was observed, suggesting that the subunit dissociation and unfolding occur simultaneously. While quenching of the protein intrinsic fluorescence by acrylamide increased significantly upon carbohydrate binding, quenching by succinimide is essentially unaffected. We attribute this difference to increased exposure of Trp-123 in the α-chain as it is involved in carbohydrate binding. Both acrylamide and succinimide gave biphasic Stern-Volmer plots, consistent with differential accessibility of the two tryptophan residues of jacalin to them.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Lectinas de Plantas / Lectinas / Neoplasias Limite: Humans Idioma: En Ano de publicação: 2024 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Lectinas de Plantas / Lectinas / Neoplasias Limite: Humans Idioma: En Ano de publicação: 2024 Tipo de documento: Article