Reversible bioconjugation as a strategy to increase photolyase solubility and stability

• Grant number: 25/03120-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: January 01, 2026
• End date: April 30, 2027
• Field of knowledge: Health Sciences - Pharmacy
• Principal Investigator: Carlota de Oliveira Rangel Yagui
• Grantee: Leticia Claudia da Silva
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The enzyme photolyase works by promoting the repair of DNA damaged by UV radiation, restoring DNA integrity, and preventing the appearance of mutations that can lead to carcinogenesis. Since all individuals are subject to excessive sun exposure daily, topical use of this enzyme is advantageous in preventing the appearance of skin cancer. Nonetheless, photolyase presents low solubility and usually aggregates in aqueous solutions, therefore research alternatives to improve its performance and management, such as bioconjugation. Bioconjugation with natural polymers such as hyaluronic acid (HA) promotes improved stability of the molecules, in addition to enhancing skin hydration and firmness when used topically. Thus, the objective of this work is to investigate the photolyase bioconjugation with HA through a disulfide bond. This chemical bond undergoes cleavage in the presence of UV radiation therefore allowing the release of the enzyme to repair the skin exposed to solar radiation. The enzyme will be produced from the cultivation of the recombinant E. coli BL21 (DE3) strain containing the Thermus thermophilus photolyase gene. The 6,000 Da hyaluronic acid will be previously thiolated and then conjugated with the enzyme. The HA-photolyase complex will be investigated regarding aqueous solubility, storage stability and in vitro release of the enzyme upon exposure to solar irradiation. We expect to produce a hyaluronic acid-photolyase bioconjugate with improved solubility and stability. (AU)