The Team

Abdullah Albalawi, Doctoral Student
Omar Castillo, Doctoral Student
Kiara Fenner, Doctoral Student
Gisele George, Doctoral Student
Jasmyn Johnson, Doctoral Student
Charles Cordts, Undergraduate Research Student
Jonathan Saenz, Undergraduate Research Student
Esteban Ramirez, Postgraduate Research Assistant
Nicholas Porter, Undergraduate Research Student
Tessa Hebert, Undergraduate Research Student
Jacqueline Bates, Undergraduate Research Student

ABOUT

Welcome to the webpage of the Molecular Biophysics group at the University of Texas at San Antonio.

The research activity in the group is focused on the development, the fundamental biophysical characterization and the applications of artificial photoreceptors. We investigate how photosensitizers conjugated to protein models can transform them into novel photoreceptor with non-native structural and functional properties

We also study the application of the protein/dye conjugates as vehicles to deliver the photosensitizers for biomedical applications.

lorenzo.brancaleon@utsa.edu

CURRENT RESEARCH ACTIVITY

The overarching research activity of the group focuses on the engineering and application of artificial photoreceptors.

Photoreceptors are ubiquitous in nature. Almost every organism possesses at least one type of photoreceptor.

In general photoreceptors are systems evolved by organisms to convert the most inexhaustible source of energy (sunlight) into usable source of energy.

Plants, algae, bacteria, etc. are obvious examples where photoreceptors mediated the conversion of photon energy into storable fuel (e.g., carbohydrates).

Vision is another example of a sophisticated mechanism that depends on the conversion of photon energy. In this case photoreceptors mediate photon energy into electrical signals in excitable membranes. Many other examples of sophisticated photoreceptors exist in nature.

Almost always photoreceptors are constructs between a relatively small photoactive molecule and a protein. There are several types of photoactive molecules used by nature for photoconversion mechanisms: retinols, flavins, porphyrins, etc.

We are investigating the possibility to use this concept to turn into photoreceptors, proteins that natively do not have such property. These are what we define as ARTIFICIAL PHOTORECEPTORS.

We are considering a subset of globular proteins (such as albumin, lactoglobulin, lysozyme, etc.) and a series of photosensitizers, and i9nvestigate whether the photosensitizire donate light-induced functionality to the protein.

MODIFICATION OF PHOTOSENSITIZERS

INTERACTION OF PHOTOSENSITIZERS WITH PROTEIN MODELS

CONFORMATIONAL EFFECTS ON PROTEINS

In collaboration with the group of Dr. George Negrete in the Department of Chemistry we are functionalizing photosensitizers with maleimide, chloroacetyl or iodoacetyl groups in order to conjugate the photoactive molecules to proteins.

We are characterizing the non-covalent interactions between photosensitizers and proteins.
We are also characterizing biomolecular nanostructures formed by conjugating photosensitizers to free cysteines in protein containing a single cysteine residue.

We investigate whether the photosensitization causes conformational changes that can be linked to light-induced, non-native functional properties to the proteins.

ARTIFICIAL PHOTORECEPTORS FOR DRUG DELIVERY

PHOTOINACTIVATION OF MICROORGANISMS

EFFECTS OF PLASMONICS ON PROTEIN STRUCTURE AT THE INTERFACE WITH METAL NANOPARTICLES

We are investigating how the principles of artificial photoreceptors can be used to improve drug delivery to cancer cells.

We are investigating the use of protein/photosensitizers conjugates to target specifically microorganisms that cause food-borne and water-borne contamination.

We investigate experimentally and computationally the effect of the temperature rise caused by plasmonic modes on proteins adsrobed onto metal nanoparticles