Biology subjects

Jorgensen, F. S.

Publications and source records attributed to Jorgensen, F. S..

4 recordsLinked to original sources

bioRxiv2023

Essential oil terpenes may inhibit steroidogenic cytochrome P450 activities.

Endocrine-disrupting chemicals (EDCs) may impact the development of Prostate Cancer (PCa) by altering the steroid metabolism. Although their exact mechanism of action in controlling tumor growth is not known, EDCs may inhibit steroidogenic enzymes such as Cytochrome P450 c17 (CYP17A1) or aromatase (CYP19A1) involved in the production of Androgens or Estrogens. High levels of circulating androgens are linked to PCa in men and Polycystic Ovary Syndrome (PCOS) in women. Essential Oils or their metabolites (EOs) like lavender oil and tea tree oil have been reported to act as potential EDCs and contribute towards sex steroid imbalance in case of prepubertal gynecomastia in boys and premature thelarche in girls due to the regular exposure to lavender-based fragrances among Hispanic population. We screened a range of EO components to determine their effects on CYP17A1 and CYP19A1 Computational docking was performed to predict the binding of EOs with CYP17A1 and CYP19A1 and functional assays were done using the radiolabeled substrates or Liquid Chromatography high-resolution Mass Spectrometry and cell viability assays were carried out in LNCaP cells. Many of the tested compounds bind close to the active site of CYP17A1, and (+)-Cedrol had the best binding with CYP17A1 and CYP19A1. Eucalyptol, Dihydro-{beta}-Ionone & (-)--pinene showed 20% to 40% inhibition of dehydroepiandrosterone production; and some compounds also effected CYP19A1. Extensive use of these EOs in various beauty and hygiene products is common, but only a limited knowledge about their potential detrimental side effects exists. Our results suggest that prolonged exposure to some of these essential oils may result in steroid imbalances. On the other hand, due to their effect on lowering androgen output, ability to bind at the active site of steroidogenic cytochrome P450s, these compounds may provide design ideas for the novel compounds against hyperandrogenic disorders such as PCa and PCOS.

pharmacology and toxicology↗

bioRxiv2023

Mechanistic insight into substrate specificity of plant glucosinolate transporters

Plants depend on transport processes for correct allocation of specialized metabolites. This is important for optimal defense, avoidance of autotoxicity, connecting compartmented biosynthetic modules and more. Transport of a wide variety of specialized metabolites is mediated by transporters from the Nitrate and Peptide transporter Family (NPF), which belongs to the Major Facilitator Superfamily (MFS). However, the mechanism by which NPF members recognize and transport specialized metabolites remains unknown. Here we mutate eight residues to reciprocally swap the substrate-preference of two closely related glucosinolate transporters (GTRs). Seven of these residues assemble in a ring-like structure in all conformations of the transporters. We labeled the ring-like structure a selectivity filter and based on docking studies, we propose that the interaction between the selectivity filter and the glucosinolate side chain determines whether a given glucosinolate is recognized as a substrate. Besides partly explaining the distinct substrate preference of GTR1 (NPF2.10) and GTR3 (NPF2.9), this study proposes fundamental principles of substrate recognition in the NPF and establishes the GTR subclade as a novel model system for studying structure function relationships in the NPF.

molecular biology↗

bioRxiv2020

Across kingdom biased CYP-mediated metabolism via small-molecule ligands docking on P450 oxidoreductase

Metabolic control is mediated by the dynamic assemblies and function of multiple redox enzymes. A key element in these assemblies, the P450 oxidoreductase (POR), donates electrons and selectively activates numerous (>50 in humans and >300 in plants) cytochromes P450 (CYPs) controlling metabolism of drugs, steroids and xenobiotics in humans and natural product biosynthesis in plants. The mechanisms underlying POR-mediated CYP metabolism remain poorly understood and to date no ligand binding has been described to regulate the specificity of POR. Here, using a combination of computational modeling and functional assays, we identified ligands that dock on POR and bias its specificity towards CYP redox partners. Single molecule FRET studies revealed ligand docking to alter POR conformational sampling, which resulted in biased activation of metabolic cascades in whole cell assays. We propose the model of biased metabolism, a mechanism akin to biased signaling of GPCRs, where ligand docking on POR stabilizes different conformational states that are linked to distinct metabolic outcomes. Biased metabolism may allow designing pathway-specific therapeutics or personalized food suppressing undesired, disease related, metabolic pathways.

biophysics↗

bioRxiv2019

An Optimized Screen Reduces the Number of GA Transporters and provides Insights into NPF Substrate Determinants

Based on recent in vitro data, a relatively large number of the plant Nitrate transporter 1/Peptide transporter Family (NPF) proteins has been suggested to function as gibberellic acid (GA) transporters. Most GA transporting NPF proteins also appear to transport other structurally unrelated phytohormones or metabolites. Several of the GAs used in previous in vitro assays are membrane permeable weak organic acids whose movement across membranes are influenced by the pH-sensitive ion-trap mechanism. Moreover, a large proportion of in vitro GA transport activities have been demonstrated indirectly via long-term yeast-based GA-dependent growth assays that are limited to detecting transport of bioactive GAs. Thus, there is a need for an optimized transport assay for identifying and characterizing GA transport. Here, we develop an improved transport assay in Xenopus laevis oocytes wherein we directly measure movement of six different GAs across oocyte membranes over short time. We show that membrane permeability of GAs in oocytes can be predicted based on number of oxygen atoms and that several GAs do not diffuse over membranes regardless of changes in pH values. In addition, we show that small changes in internal cellular pH can result in strongly altered distribution of membrane permeable phytohormones. This prompts caution when interpreting heterologous transport activities. We use our transport assay to screen all Arabidopsis thaliana NPF proteins for transport activity towards six GAs (two membrane permeable and four non-permeable). The results presented here, significantly reduce the number of bona fide NPF GA transporters in Arabidopsis and narrow the activity to fewer subclades within the family. Furthermore, to gain first insight into the molecular determinants of substrate specificities towards organic molecules transported in the NPF, we charted all surface exposed amino acid residues in the substrate-binding cavity and correlated them to GA transport. This analysis identified distinct residues within the substrate-binding cavity that are shared between GA transporting NPF proteins; the potential roles of these residues in determining substrate specificity are discussed.

biochemistry↗