exploring-biomolecular-interaction-between-molecular-chaperone-hsp90

Exploring Biomolecular Interaction Between the Molecular Chaperone Hsp90 and Its Client Protein Kinase Cdc37 using Field-Effect Biosensing Technology

Biomolecular interactions play versatile roles in numerous cellular processes&#160;by regulating and coordinating functionally relevant biological events. ...

Bar Ilan University

Bar-Ilan University

Proteins may utilize complex networks of interactions to create/proceed signaling pathways of highly adaptive responses such as programmed cell death. Direct binary interactions study of proteins may help propose models for protein-protein interaction. Towards this goal we applied a combination of thermodynamic kinetics and crystal structure analyses to elucidate the complexity and diversity in such interactions. By determining the heat change on the association of two galactose-specific legume lectins from Butea monosperma (BML) and Spatholobus parviflorus (SPL) belonging to Fabaceae family helped to compute the binding equilibrium. It was extended further by X-ray structural analysis of BML-SPL binary complex. In order to chart the proteins interacting mainly through their interfaces, identification of the nature of forces which stabilized the association of the lectin-lectin complex was examined. Comprehensive analysis of the BMLSPL complex by isothermal titration calorimetry and X-ray crystal structure threw new light on the lectin-lectin interactions suggesting of their use in diverse areas of glycobiology. 

A profile of protein-protein interaction: Crystal structure of a lectin-lectin complex.

Glycan recognition is the most attractive defining feature of lectins, and also they exhibit specific phytochemical interactions at distinct sites without interfering the glycocode recognition capability. These additional sites may be viewed as potential drug carrying sites that could be exploited for targeted drug delivery. The pharmacological effects of quercetin (QN) have already been studied. However, its molecular mechanism of interactions with lectin has not yet been addressed. The extending novelty provokes us to unravel the binding profile of QN with Spatholobus parviflorus lectin (SPL) using a combination series of biophysical and computational approaches. The UV absorption studies revealed an intense SPL-QN complex formation, indicating a hyperchromic effect. The fluorescence spectroscopic analysis using sugar-free SPL and sugar saturated SPL (ssSPL) revealed that QN binding significantly quenched the intrinsic fluorescence of SPL. The thermodynamic parameters maintained uniformity with the binding stoichiometry (n = 4) of both SPL and ssSPL, hence it may be assumed that the sugar binding onto the SPL would not have been influenced with QN binding. The molecular docking analysis also maintained consistency with the in vitro results. It could be concluded from SPL-QN interactions without altering unique carbohydrate specificities, leave SPL unrestricted for other molecular recognition events.

Article	Year
A profile of protein-protein interaction: Crystal structure of a lectin-lectin complex. International journal of biological macromolecules\| PubMed ID: 26945504	2016
Quercetin binding to Spatholobus parviflorus lectin: Promise of a macromolecular, specific-compound carrier for drug. International journal of biological macromolecules\| PubMed ID: 30991071	2019

Surya Sukumaran

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