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We report two BODIPY based photosensitizers (Br2BOAc and I2BOAc) featuring an acetoxymethyl substituent at the meso-position. These photosensitizers show improved photostability against singlet oxygen, when compared to a BODIPY photosensitizer lacking the acetoxymethyl group. Both compounds were evaluated for photodynamic therapy against HeLa cells and photodynamic inactivation against E. coli bacteria. We show that the compounds readily embed in the lipid membranes of HeLa cervical cancer cells and efficiently induced light-dependent apoptosis at nanomolar concentration. Also, both compounds showed a substantial degree of photoinactivation of E. coli bacteria when used at low micromolar concentrations.

Intrinsically disordered proteins (IDPs) have long been a challenge to structural biologists due to their lack of stable secondary structure elements. Hydrogen-Deuterium Exchange (HDX) measured at rapid time scales is uniquely suited to detect structures and hydrogen bonding networks that are briefly populated, allowing for the characterization of transient conformers in native ensembles. Coupling of HDX to mass spectrometry offers several key advantages, including high sensitivity, low sample consumption and no restriction on protein size. This technique has advanced greatly in the last several decades, including the ability to monitor HDX labeling times on the millisecond time scale. In addition, by incorporating the HDX workflow onto a microfluidic platform housing an acidic protease microreactor, we are able to localize dynamic properties at the peptide level. In this study, Time-Resolved ElectroSpray Ionization Mass Spectrometry (TRESI-MS) coupled to HDX was used to provide a detailed picture of residual structure in the tau protein, as well as the conformational shifts induced upon hyperphosphorylation.

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