BODIPY-Based Fluorescent Probes for Sensing Protein Surface-Hydrophobicity

Abstract

Mapping surface hydrophobic interactions in proteins is key to understanding molecular recognition, biological functions, and is central to many protein misfolding diseases. Herein, we report synthesis and application of new BODIPY-based hydrophobic sensors (HPsensors) that are stable and highly fluorescent for pH values ranging from 7.0 to 9.0. Surface hydrophobic measurements of proteins (BSA, apomyoglobin, and myoglobin) by these HPsensors display much stronger signal compared to 8-anilino-1-naphthalene sulfonic acid (ANS), a commonly used hydrophobic probe; HPsensors show a 10- to 60-fold increase in signal strength for the BSA protein with affinity in the nanomolar range. This suggests that these HPsensors can be used as a sensitive indicator of protein surface hydrophobicity. A first principle approach is used to identify the molecular level mechanism for the substantial increase in the fluorescence signal strength. Our results show that conformational change and increased molecular rigidity of the dye due to its hydrophobic interaction with protein lead to fluorescence enhancement.

Interaction of BODIPY dyes with bovine serum albumin: a case study on the aggregation of a click-BODIPY dye

“…Potentially the disaggregation of click-BODIPY dyes could be used as a detection event 21 as well as a sensor for the hydrophobic surfaces of the proteins. 14 …”

“…11,12 Significantly, specifically substituted BODIPY-based fluorescent probes were shown to be viable sensors of protein hydrophobicity. 14 Furthermore, several common BODIPY dyes, including a water-soluble derivative, were recently suggested to interact with albumins 15 as was evidenced by an increased in the emission intensity.…”

A screening platform based on epitope editing for drug discovery

“…To further confirm whether CRANAD-17 could lead to changes of epitope hydrophobicity, fragment Aβ17-24 and full-length of Aβ were used in ANS (1-anilino-8naphthalenesulfonate) fluorescence assay, which is commonly used for measuring protein surface hydrophobicity. 20,21 Normalized fluorescence intensity was plotted against protein concentration, and the slope was used as a hydrophobicity index to evaluate change. As shown in Fig.2g and Supplementary Fig.5, the hydrophobic index of Aβ significantly changed upon mixing with CRANAD-17, indicating alteration of epitope hydrophobicity.…”

“…Recently, blocking the PD-1/PD-L1 pathway has become one of the most promising strategies in cancer therapy and several monoclonal antibodies are currently on the market or in the process of FDA approval. 32,33 Anti-PD-L1 antibody , which targets the specific extracellular domain of Phe19-Thr239 of PD-L1, and two classes of reported PD-L1 inhibitors 20 include small molecule BMS-202 and peptide WL12 were selected for the testing. 32,33 As shown in Fig.6e-h, the readout of WL12 significantly decreased while BMS-202 displayed no obvious change compared to the blank control.…”

Facile and High-Throughput Synthesis of Functional Microparticles with Quick Response Codes

“…This suggests that BDP‐M encoded particles to be used in bioassays may be transported or stored in these conditions, although long‐term stability in aqueous solution was not monitored. The retention of BDP‐M dye in the microparticles may be explained by the cross‐linking of BDP‐M with thiolated components of the polymer via thiol‐maleimide reaction and by BDP‐M's lack of ionic charge, which promotes its association with the similarly hydrophobic thiol‐ene polymer matrix and limits its solubility in water …”