Research in the Protein Chemistry Laboratory is aimed at an understanding of protein interactions with small molecules, other proteins and nanoparticles. The increasing use of peptides as therapeutics has prompted us to look into the various aspects of these interactions to try and understand the impact on disease related processes.
A brief outline of the different projects:
Protein aggregation studies: Aggregation studies currently underway involve several proteins as well as the amyloid peptide fragment Ab25-35which represents the biologically active and toxic domain of the full length Aβ peptide, responsible for Alzheimer’s disease. Inhibition of amyloid fibrillation of the Aβ25-35 peptide was achieved by adhesion of the peptide on a graphene oxide (GO) surface and treating the peptides with HCTL, an amine oxide osmolyte, and glycerol. Factors that inhibit and accelerate fibrillation through amino acid modifications and electrostatic interactions among the peptide units and additives have also been identified.
Studies with the eye lens proteins: Owing to the loss of native structure due to several factors like ageing, mutations in the genes, oxidation of the proteins, UV induced oxidative damage, the crystallin proteins of the eye lens aggregate, leading to cataract formation. The major polyphenol present in green tea, EGCG was able to prevent tryptophan oxidation of cataractous ocular lens human γ-crystallin in presence of H2O2. The discarded emulsion of the eye lens has also been used to prepare biodegradable and biocompatible protein nanoparticles and thin films.
Protein ligand binding: Studies with ribonucleases, such as Ribonuclease A and angiogenin,are underway with synthetic as well as natural inhibitors. Green tea polyphenols behave as noncompetitive inhibitors of Ribonuclease A and angiogenin. Methods are being developed to investigate the angiogenesis potency of the compounds by in vitro and in vivo studies.
Interactions of proteins with gold nanoparticles: Gold nanoparticles are studied for therapeutic use in the targeted delivery of various biomolecules. After introduction of nanoparticles (NP) into biological fluids,an NP–protein complex is formed and the adsorption of proteins on nanoparticles forms a protein corona. A protein corona using HSA and gold nanoparticles has been prepared and the interactions and structural changes are being looked into.
What are the challenges that the research will help address?
Each of the topics deals with a perspective that helps us study the problems from the protein level. For example, we look at the changes in the γ-crystallin protein that have occurred as a result of cataract formation or how the enzymatic and angiogenic activity of angiogenin may be affected with small molecule inhibitors. The model protein Ribonuclease A for the latter studies is also of interest and synthesized molecules are being screened in collaborative research activities. The study mainly focuses on the mode of binding and gives us an insight into the substrate binding site, which provides rational guidelines for the design compounds of pharmaceutical targets to angiogenin. Work with polyphenols and surfactants on the fibrillation of proteins have been initiated to study the amyloid fibrils, the hallmark of neurodegenerative diseases. These are small attempts to address common problems from a molecular standpoint.
In what stage of development is this research?
The research conducted is in vitro and at the basic molecular level. It needs to be translated to an in vivo stage to be able to understand it from a physiological point of view. At present work on different projects range from preliminary to mid stage. For example, studies need to be conducted on other variants of crystallins. The ability of the designed compounds to inhibit the enzymatic and/or biological activity would need to be tested in vivo. Film properties need to be enhanced and cell compatibility, cell growth, etc. need to be investigated. However, some of the activities could be taken further at their current status.
What is its future?
There is expected to be an exponential rise in nanomedicinal chemistry which could help resolve critical health issues in future. Studies to analyze or predict and control the fate of drug-loaded nanoparticles and the various biological responses such as fibrillation, cellular uptake, systemic circulation, biodistribution and bioavailability are essential. Potential information about interaction of specific molecules with participating amino acids in the active site or an understanding of the mechanism of amyloid fibrillation process and its inhibition strategies in general are currently underway.
How will the upcoming hospital – Dr. B.C. Roy Institute of Medical Science and Research – help this work?
Basic research in the disease arena would require essential samples like blood, tissue samples etc. The study of various compounds/drugs can be performed by comparing the effects on normal as well as cancer cells. The hospital can also provide us with the eye lens emulsion obtained after cataract surgery required for our studies.
Pix: Suman Sutradhar (Prof. Dasgupta)