Search

Cytochrome P450 enzymes are monooxygenases widely diffused in nature ranging from viruses to man. They can catalyze a very wide range of reactions, including the ketonization of C–H bonds, N/O/S-dealkylation, C–C bond cleavage, N/S-oxidation, hydroxylation, and the epoxidation of C=C bonds. Their versatility makes them valuable across various fields such as medicine, chemistry, and food processing. In this review, we aim to highlight the significant contribution of P450 enzymes to fruit quality, with a specific focus on the ripening process, particularly in grapevines. Grapevines are of particular interest due to their economic importance in the fruit industry and their significance in winemaking. Understanding the role of P450 enzymes in grapevine fruit ripening can provide insights into enhancing grape quality, flavor, and aroma, which are critical factors in determining the market value of grapes and derived products like wine. Moreover, the potential of P450 enzymes extends beyond fruit ripening. They represent promising candidates for engineering crop species that are resilient to both biotic and abiotic stresses. Their involvement in metabolic engineering offers opportunities for enhancing fruit quality attributes, such as taste, nutritional content, and shelf life. Harnessing the capabilities of P450 enzymes in crop improvement holds immense promise for sustainable agriculture and food security. [ABSTRACT FROM AUTHOR]

Strigolactones (SLs) are carotenoid-derived phytohormones governing a wide range of physiological processes, including drought-associated stomatal closure. We have previously shown in tomato that SLs regulate the so-called after-effect of drought, whereby stomatal conductance is not completely restored for some time during recovery after a drought spell, irrespective of the water potential. To ease the elucidation of its molecular underpinnings, we investigated whether this SL effect is conserved in Arabidopsis thaliana by contrasting the physiological performances of the wild-type with SL-depleted (more axillary growth 4, max4) and insensitive (dwarf 14, d14) mutants in a drought and recovery protocol. Physiological analyses showed that SLs are important to achieve a complete after-effect in A. thaliana , while transcriptome results suggested that the SL-dependent modulation of drought responses extends to a large subset (about 4/5) of genes displaying memory transcription patterns. Among these, we show that the activation of over 30 genes related to abscisic acid metabolism and signaling strongly depends on SL signaling. Furthermore, by using promoter-enrichment tools, we identified putative cis - and trans -acting factors that may be important in the SL-dependent and SL-independent regulation of genes during drought and recovery. Finally, in order to test the accuracy of our bioinformatic prediction, we confirmed one of the most promising transcription factor candidates mediating SL signaling effects on transcriptional drought memory—BRI-EMS SUPPRESSOR1 (BES1). Our findings reveal that SLs are master regulators of Arabidopsis transcriptional memory upon drought and that this role is partially mediated by the BES1 transcription factor. [ABSTRACT FROM AUTHOR]

A gene coding for a class VII cytochrome P450 monooxygenase ( CYP116B5) was identified from A cinetobacter radioresistens S13 growing on media with medium ( C14, C16) and long ( C24, C36) chain alkanes as the sole energy source. Phylogenetic analysis of its N- and C-terminal domains suggests an evolutionary model involving a plasmid-mediated horizontal gene transfer from the donor R hodococcus jostii RHA1 to the receiving A . radioresistens S13. This event was followed by fusion and integration of the new gene in A . radioresistens chromosome. Heterologous expression of CYP116B5 in E scherichia coli BL21, together with the A . radioresistens Baeyer- Villiger monooxygenase, allowed the recombinant bacteria to grow on long- and medium-chain alkanes, showing that CYP116B5 is involved in the first step of terminal oxidation of medium-chain alkanes overlapping AlkB and in the first step of sub-terminal oxidation of long-chain alkanes. It was also demonstrated that CYP116B5 is a self-sufficient cytochrome P450 consisting of a heme domain (aa 1-392) involved in the oxidation step of n-alkanes degradation, and its reductase domain (aa 444-758) comprising the NADPH-, FMN- and [ 2Fe2S]-binding sites. To our knowledge, CYP116B5 is the first member of this class to have its natural substrate and function identified. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is a global issue currently resulting in the deaths of hundreds of thousands of people a year worldwide. Data present in the literature illustrate the emergence of many bacterial species that display resistance to known antibiotics; Acinetobacter spp. are a good example of this. We report here that Acinetobacter radioresistens has a Baeyer-Villiger monooxygenase (Ar-BVMO) with 100% amino acid sequence identity to the ethionamide monooxygenase of multidrug-resistant (MDR) Acinetobacter baumannii. Both enzymes are only distantly phylogenetically related to other canonical bacterial BVMO proteins. Ar-BVMO not only is capable of oxidizing two anticancer drugs metabolized by human FMO3, danusertib and tozasertib, but also can oxidize other synthetic drugs, such as imipenem. The latter is a member of the carbapenems, a clinically important antibiotic family used in the treatment of MDR bacterial infections. Susceptibility tests performed by the Kirby-Bauer disk diffusion method demonstrate that imipenem-sensitive Escherichia coli BL21 cells overexpressing Ar-BVMO become resistant to this antibiotic. An agar disk diffusion assay proved that when imipenem reacts with Ar-BVMO, it loses its antibiotic property. Moreover, an NADPH consumption assay with the purified Ar-BVMO demonstrates that this antibiotic is indeed a substrate, and its product is identified by liquid chromatography-mass spectrometry to be a Baeyer-Villiger (BV) oxidation product of the carbonyl moiety of the β-lactam ring. This is the first report of an antibiotic-inactivating BVMO enzyme that, while mediating its usual BV oxidation, also operates by an unprecedented mechanism of carbapenem resistance., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)