Biology subjects

Udayanga, D. M. N.

Publications and source records attributed to Udayanga, D. M. N..

2 recordsLinked to original sources

bioRxiv2026

Paired-probe chemoproteomic strategy enables global site-resolved quantification of lysine redox states

Site-specific quantification of lysine (Lys) redox states remains unexplored, as current approaches identify only a limited number of modification sites without determining their stoichiometry. Allysine, an oxidized form of Lys, provides a model posttranslational modification (PTM) for addressing this challenge by requiring selective enrichment and site-specific stoichiometric quantification. Here, we developed a quantitative chemoproteomic platform for paired redox-state isotopic stoichiometry mapping of lysine, termed PRISM-Lys. We used an Am-alkyne probe for allysine enrichment by reductive amination and developed a complementary Ald-alkyne probe to label Lys, with identical reactions generating the same chemical product. Coupling this paired-probe strategy with a quantitative chemoproteomic workflow enables global site-resolved quantification and stoichiometric analysis of Lys redox states across cells and tissues. Applied to ferroptosis, PRISM-Lys revealed bidirectional, site-selective remodeling of Lys oxidation events associated with ferroptotic progression. Together, PRISM-Lys establishes a paired-chemistry framework for global, site-resolved quantification of Lys redox states, providing a new quantitative perspective for investigating protein oxidation in biological systems.

biochemistry↗

bioRxiv2025

Ciclopirox suppresses poxvirus replication by targeting iron metabolism

Poxviruses remain a significant global health concern, necessitating the development of novel antiviral strategies. Through high-throughput screening, we previously identified ciclopirox (CPX), an FDA-approved antifungal, as a hit that inhibits vaccinia virus (VACV) replication. Here, we further characterized its antiviral activity and mechanism of action using human primary fibroblasts. CPX significantly reduced VACV titers without reducing host cell viability, with an EC50 in the sub-micromolar range and a CC50 >500 M. Rescue experiments demonstrated that CPX inhibits viral replication primarily through chelation of intracellular Fe3+ and, to a lesser extent, Fe2+, as evidenced by partial restoration of viral replication with ferric ammonium citrate supplementation. Furthermore, overexpression of the iron-dependent enzymes RRM2 and the VACV-encoded F4L reduced the inhibitory effect of CPX, indicating that these host and viral proteins are affected by CPX treatment. Moreover, CPX treatment also suppressed cowpox virus and monkeypox (mpox) virus replication in vitro. It also reduced VACV titers in ex vivo mouse lung tissue. These findings highlight host iron metabolism as a critical determinant of poxvirus replication and support repurposing CPX as a broad-spectrum orthopoxvirus antiviral candidate.

microbiology↗