4 research outputs found
Structural analysis of a simplified model reproducing SARS-CoV-2 S RBD/ACE2 binding site
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an RNA virus identified as the cause of the coronavirus outbreak in December 2019 (COVID-19). Like all the RNA viruses, SARS-CoV-2 constantly evolves through mutations in its genome, accumulating 1–2 nucleotide changes every month, giving the virus a selective advantage through enhanced transmissibility, greater pathogenicity, and the possibility of circumventing immunity previously acquired by an individual either by natural infection or by vaccination. Several SARS-CoV-2 variants of concern (VoC) have been identified, among which we find Alpha (Lineage B.1.1.7), Beta (Lineage B.1.351), and Gamma (Lineage P.1) variants. Most of the mutations occur in the spike (S) protein, a surface glycoprotein that plays a crucial role in viral infection; the S protein binds the host cell receptor, the angiotensin-converting enzyme of type 2 (ACE2) via the receptor binding domain (RBD) and catalyzes the fusion of the viral membrane with the host cell. In this work, we present the development of a simplified system that would afford to study the change in the SARS-CoV-2 S RBD/ACE2 binding related to the frequent mutations. In particular, we synthesized and studied the structure of short amino acid sequences, mimicking the two proteins’ critical portions. Variations in the residues were easily managed through the one-point alteration of the sequences. Nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopies provide insights into ACE2 and SARS-CoV-2 S RBD structure with its related three variants (Alpha, Beta, and Gamma). Spectroscopy data supported by molecular dynamics lead to the description of an ACE2/RBD binding model in which the effect of a single amino acid mutation in changing the binding of S protein to the ACE2 receptor is predictable
Ganoderma lucidum Ethanol Extracts Enhance Re-Epithelialization and Prevent Keratinocytes from Free-Radical Injury
Ganoderma lucidum or Reishi is recognized as the most potent adaptogen present in
nature, and its anti-inflammatory, antioxidant, immunomodulatory and anticancer activities are well
known. Moreover, lately, there has been an increasing interest from pharmaceutical companies in
antiaging G. lucidum-extract-based formulations. Nevertheless, the pharmacological mechanisms
of such adaptogenic and regenerative actions remain unclear. The present investigation aimed to
explore its molecular and cellular eects in vitro in epidermal keratinocyte cultures by applying
liquid chromatography coupled to ion trap time-of-flight mass spectrometry (LCMS-IT-TOF) for
analysis of ethanol extracts using ganoderic acid-A as a reference compound. The G. lucidum
extract showed a keratinocyte proliferation induction accompanied by an increase of cyclic kinase
protein expressions, such as CDK2 and CDK6. Furthermore, a noteworthy migration rate increase
and activation of tissue remodelling factors, such as matrix metalloproteinases 2 and 9 (MMP-2
and MMP-9), were observed. Finally, the extract showed an antioxidant eect, protecting from
H2O2-induced cytotoxicity; preventing activation of AKT (protein kinase B), ERK (extracellular
signal-regulated kinase), p53 and p21; and reducing the number of apoptotic cells. Our study paves
the path for elucidating pharmacological properties of G. lucidum and its potential development as
cosmeceutical skin products, providing the first evidence of its capability to accelerate the healing
processes enhancing re-epithelialization and to protect cells from free-radical action
Towards an Improvement of Anticancer Activity of Benzyl Adenosine Analogs
N6-Isopentenyladenosine (i6A) is a naturally occurring modified nucleoside displaying in vitro and in vivo antiproliferative and pro-apoptotic properties. In our previous studies, including an in silico inverse virtual screening, NMR experiments and in vitro enzymatic assays, we demonstrated that i6A targeted farnesyl pyrophosphate synthase (FPPS), a key enzyme involved in the mevalonate (MVA) pathway and prenylation of downstream proteins, which are aberrant in several cancers. Following our interest in the anticancer effects of FPPS inhibition, we developed a panel of i6A derivatives bearing bulky aromatic moieties in the N6 position of adenosine. With the aim of clarifying molecular action of N6-benzyladenosine analogs on the FPPS enzyme inhibition and cellular toxicity and proliferation, herein we report the evaluation of the N6-benzyladenosine derivatives’ (compounds 2a–m) effects on cell viability and proliferation on HCT116, DLD-1 (human) and MC38 (murine) colorectal cancer cells (CRC). We found that compounds 2, 2a and 2c showed a persistent antiproliferative effect on human CRC lines and compound 2f exerted a significant effect in impairing the prenylation of RAS and Rap-1A proteins, confirming that the antitumor activity of 2f was related to the ability to inhibit FPPS activity