Biology subjects

Bjerring, P.

Publications and source records attributed to Bjerring, P..

3 recordsLinked to original sources

bioRxiv2024

New insight into erythema reduction induced by quercetin metal ions chelates

In dermatology, chelates play a significant role in skin care and treatment of skin diseases. Chelates involve coordination bonding between metal ions and organic molecules such as flavonoids. Quercetin (Q) is an extensively studied natural flavonoid with proven safety and anti-inflammatory properties. This study shows the role of two biocompatible metal ions, Iron (Fe2+) and Copper (Cu2+) in coordination bonding with Q in 2-Propanol 50% and 80% at 1:1 stoichiometry. Our results show that chelation involves the hydroxyl groups and occurs by coordination of Cu2+ to Q for the Ring A-B (Benzoyl group) resulting in a fluorescence emission peak at 530nm from the Ring B-C (Cinnamoyl group). This chelates Q+Cu2+ reduces mechanically induced erythema in the skin (Tanned type). A similar effect was observed in the chelate Q+Fe2+ where the coordination of Fe2+ to Q occurs for the cinnamoyl group resulting in an emission peak at 425nm from Benzoyl group of Q. The statistical analysis shows significant differences in the effects of Q+Cu2+ (p-value = 0.00001), Q+Fe2+ (p-value = 0.0003) respect to Q as well as between them (p-value =0.0029). Our results suggest that the interaction between Q and metal ions plays a central role in the inflammatory pathway. We conclude that the anti-inflammatory properties of Q were enhanced by both Q+Fe2+ and Q+Cu2+ chelates, highlighting the effect of Q+Fe2+ where the hydroxyl groups available in the cinnamoyl group of the Q molecule are the main intermediates to interact with Fe2+, which is a requirement to trigger the anti-inflammatory molecular events of Q molecules.

biophysics↗

bioRxiv2024

Observing picomolar protein unfolding using resonance light scattering

We here present a novel and sensitive methodology for determining the melting point (MP) of Bovine Serum Albumin (BSA) from micromolar to picomolar concentration levels under label free conditions. At 1 pM we could model the melting with a sharp gaussian. However, from the transient state observed during the melting process by using a simple exponential decay model we determined a time constant of 67 seconds. We applied this methodology by studying a 3.3 pM sample of a botulinum toxin A (BoNT-A) (stabilized with 2.8 nanomolar denatured Human Serum Albumin (HSA)). We were able to determine the Tm of BoNT-A in the presence of the approximately 1000-fold more concentrated HSA. Entry for the Table of Contents O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=153 SRC="FIGDIR/small/624557v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@12d93a7org.highwire.dtl.DTLVardef@138d01dorg.highwire.dtl.DTLVardef@e725acorg.highwire.dtl.DTLVardef@15a5f77_HPS_FORMAT_FIGEXP M_FIG C_FIG Protein label-free melting point (MP) determination at ultralow concentrations is a huge problem which concern to the biopharmaceutical industry. Here, we present a novel method to determine the MP of bovine serum albumin (BSA) from 1M to 1pM under label-free conditions. The benefits of this study match the purposes of stability studies in formulations, in which the protein active component is successful at very low concentrations, such as botulinum toxin A (BoNT-A). We used BOCOUTRE, a commercially available pharmaceutical product based on BoNT-A, and Human Serum Albumin (HSA) as a stabilizer. Our method can detect the MP of the stabilizer protein, even if its concentration is markedly different from that of the active component protein (1000-fold) in the case of BOCOUTRE.

biophysics↗

bioRxiv2024

Modifying the aggregation state may improve the activity of Ozempic

We here report a study of aggregation of Semaglutide at different temperatures, using resonance light scattering (RLS), fluorescence polarization and back-scattering techniques. Fluorescence emission spectra were obtained by exciting the samples at 275 nm and 295 nm, revealing a peak emission at 600 nm associated with the aggregation process. The size of the aggregates is around 100 nm according to back-scattering measurements. Two distinct thermal transitions were observed by RLS: the first melting point (Tm1) at 30{degrees}C and the second (Tm2) at 91{degrees}C, indicating changes in aggregation state. The fluorescence polarization revealed a fast rotational dynamics of the aggregates at Tm2, leading to greater depolarization of the emitted light. The structural organization of the Ozempic aggregates was studied using two dyes, Laurdan for lipid components and 1,8-ANS for protein component (GLP1). Thus, revealing a stable PEG-lipid core which hold the GLP1, increasing their exposition to the solvent. An enhanced FRET event inside the aggregates in presence of Fe2+ and Fe3+ was observed. We conclude that the PEG-lipid core plays a significant role in the aggregates structure stability, being a key to improve the biological activity of Ozempic. This methodology can be used to study similar aggregation constructs in the pharmaceutical industry.

biophysics↗