Dr. Madeline TORRES

Researcher: Dr. Madeline Torres

Institution: Department of Chemical Engineering, University of Puerto Rico in Mayaguez

Project Title: Molecular Studies of Proteins Encapsulated in Soft Materials

AABRE Cluster: Drug Design & Delivery

Mentor: Dr. Juan Lopez-Garriga, University of Puerto Rico in Mayaguez

Collaborators and Consultants:

• Dr. Gustavo Lopez, University of Puerto Rico in Mayaguez
• Dr. Jorge Rios-Steiner, University of Puerto Rico in Mayaguez
• Dr. Joseph Bonaventura, University of Puerto Rico in Mayaguez
• Dr. Carmen Cadilla, University of Puerto Rico - Medical Sciences Campus

Abstract:

It is becoming apparent that hydrophobic cavities and hydrophilic environments within proteins have significant functional implications. Therefore, the use of modified polymeric matrices and sol-gels to trap heme proteins are an essential step needed in the pursuit of understanding equilibrium and non-equilibrium processes upon heme and ligand moiety interactions. This project envisions the investigation of soft materials including hydrogels and sol-gel derived materials to encapsulate proteins and to understand the protein/polymer physicochemical interactions.

These goals will be specifically achieved by:

• Encapsulation of proteins inside hydrogel networks, through both the covalent and non covalent approaches, inside hydrophilic polymeric membranes specifically designed to maximize the protein/polymer physico-chemical interactions.
• Examination of the encapsulation capacity, for the non covalent encapsulation by determining the partition coefficient and protein release utilizing various polymer morphologies.
• Use the sol-gel encapsulation and polymeric matrices protocols to trap kinetically and spectroscopic unique conformational populations of wild type, expressed, and site directed mutants of hemoglobin I from Lucina pectinata. The method will allow for direct comparison of functional and spectroscopic properties of equilibrium and non-equilibrium populations with myoglobin.
• Investigate the static and time resolved resonance Raman, UV-Vis, and transient absorption of entrapped protein inside the polymeric matrices. This will produce information about: (1) distinct conformations and ligand moieties will be characterized included HzS, 02, CO affinity measurements, (2) combination rates, (3) geminate and bimolecular recombination, after photo-dissociation for the photolabile ligands, (4) transient intermediates and functionally significant nonequilibrium protein species, (5) conformational events triggered by substrate binding, and (6) degree to which the sol-gel and polymeric matrices limits conformational change upon adding or removing substrates.
• To crystallize both the protein prior to encapsulation (native protein) and compare its structure with that obtained post encapsulation in the hydrogel. Diffraction data will be collected and processed. Protein structure will be modeled including the protein-substrate or multimeric protein complexes involved.
• To perform molecular modeling of encapsulated heme-proteins in sol-gel and polymeric materials.