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The ATP-dependent phosphorylation activity of cyclin-dependent kinase 1 (CDK1), an essential enzyme for cell cycle progression, is regulated by interactions with Cyclin-B, substrate, and Cks proteins. We have recently shown that active site acetylation in CDK1 abrogated binding to Cyclin-B which posits an intriguing long-range communication between the catalytic site and the protein-protein interaction (PPI) interface. Now, we demonstrate a general allosteric link between the CDK1 active site and all three of its PPI interfaces through atomistic molecular dynamics (MD) simulations. Specifically, we examined ATP binding free energies to CDK1 in native nonacetylated (K33wt) and acetylated (K33Ac) forms as well as the acetyl-mimic K33Q and the acetyl-null K33R mutant forms, which are accessible in vitro. In agreement with experiments, ATP binding is stronger in K33wt relative to the other three perturbed states. Free energy decomposition reveals, in addition to expected local changes, significant and selective nonlocal entropic responses to ATP binding/perturbation of K33 from the αC -helix, activation loop (A-loop), and αG - α H segments in CDK1 which interface with Cyclin-B, substrate, and Cks proteins, respectively. Statistical analysis reveals that while entropic responses of protein segments to active site perturbations are on average correlated with their dynamical changes, such correlations are lost in about 9%-48% of the dataset depending on the segment. Besides proving the bi-directional communication between the active site and the CDK1:Cyclin-B interface, our study uncovers a hitherto unknown mode of ATP binding regulation by multiple PPI interfaces in CDK1., (© 2024 The Author(s). PROTEINS: Structure, Function, and Bioinformatics published by Wiley Periodicals LLC.)

Phytoconstituent based therapies have the potential to reduce the adverse effects and enhance overall patient compliance for different diseased conditions. Embelin (EMB) is a natural compound extracted from Embelia ribes that has demonstrated high therapeutic potential, particularly as anti-inflammatory and anticancer therapeutic applications. However, its poor water solubility and low oral bioavailability limitations make it challenging to use in biomedical applications. Nanostructure-based novel formulations have shown the potential to improve physicochemical and biological characteristics of active pharmaceutical ingredients obtained from plants. Different nanoformulations that have been utilized to encapsulate/entrap EMB for various therapeutic applications are nanoliposomes, nanostructured lipid carriers, niosomes, polymeric nanoparticles, nanosuspensions, phytosomes, self nanoemulsifying drug delivery system, silver nanoparticles, microparticles, solid lipid nanoparticle, gold nanoparticles and nanomicelles. The common methods reported for the preparation of EMB nanoformulations are thin film hydration, nanoprecipitation, ethanol injection, emulsification followed by sonication. The size of nanoformulations ranged in between 50 and 345 nm. In this review, the mentioned EMB loaded nanocarriers are methodically discussed for size, shape, drug entrapment, zeta potential, in vitro release & permeation and in vivo studies. Potential of EMB with other drugs (dual drug approach) incorporated in nanocarriers are also discussed (physicochemical and preclinical characteristics). Patents related to EMB nanoformulations are also presented which showed the clinical translation of this bioactive for future utilization in different indications., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

In recent years, bioactive constituents from plants have been investigated as an alternative to synthetic approaches of therapeutics. Mangiferin (MGF) is a xanthone glycoside extracted from Mangifera indica and has shown numerous medicinal properties, such as antimicrobial, anti-diarrhoeal, antiviral, anti-inflammatory, antihypertensive, anti-tumours, and anti-diabetic effects. However, there are numerous challenges to its effective therapeutic usage, including its low water solubility, limited absorption, and poor bioavailability. Nano formulation approaches in recent years exhibited potential for the delivery of phytoconstituents with key benefits of high entrapment, sustained release, enhanced solubility, stability, improved pharmacokinetics, and site-specific drug delivery. Numerous techniques have been employed for the fabrication of MGF-loaded Nano formulations, and each technique has its advantages and limitations. The nanocarriers that have been employed to fabricate MGF nanoformulations for various therapeutic purposes include; polymeric nanoparticles, nanostructure, lipid carriers, polymeric micelles, Nano emulsions, microemulsion & self-microemulsifying drug delivery system, solid lipid nanoparticles, gold nanoparticles, carbon nanotubes, transfersomes, nanoliposomes, ethosomes & transethosomes, and glycethosomes. Different biopharmaceutical characteristics (size, shape, entrapment efficiency, zeta potential, in vitro drug release, ex vivo drug permeation,, and in vivo studies) of the mentioned MGF-loaded nanocarriers have been methodically discussed. Patent reports are also included to further strengthen the potential of MGF in the management of diseases., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Wound healing is a complex physiological process involving coordinated cellular and molecular events aimed at restoring tissue integrity. Acute wounds typically progress through the sequential phases of hemostasis, inflammation, proliferation, and remodeling, while chronic wounds, such as venous leg ulcers and diabetic foot ulcers, often exhibit prolonged inflammation and impaired healing. Traditional wound dressings, while widely used, have limitations such poor moisture retention and biocompatibility. To address these challenges and improve patient outcomes, scaffold-mediated delivery systems have emerged as innovative approaches. They offer advantages in creating a conducive environment for wound healing by facilitating controlled and localized drug delivery. The manuscript explores scaffold-mediated delivery systems for wound healing applications, detailing the use of natural and synthetic polymers in scaffold fabrication. Additionally, various fabrication techniques are discussed for their potential in creating scaffolds with controlled drug release kinetics. Through a synthesis of experimental findings and current literature, this manuscript elucidates the promising potential of scaffold-mediated drug delivery in improving therapeutic outcomes and advancing wound care practices., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

In order to find the most advantageous bioactive compounds from mulberry latex for drug development in the near future, this study was conducted to characterize and evaluate antioxidant and antimicrobial properties from four different mulberry lattices (BR-2, S-1, AR-14, and S-146). The characterization of the lattices was performed by scanning electron microscopy with energy-dispersive X-ray spectroscopy, gas chromatography coupled to mass spectroscopy, and Fourier transform infrared spectroscopy. Further, screenings of the antioxidant and antimicrobial potential of selected lattices were performed in vitro using 2,2-diphenyl-1-picrylhydrazyl assay and agar well diffusion methods, respectively. Interestingly, the outcome of the current study revealed that tested mulberry lattices contain a considerable amount of bioactive phytoconstituents, particularly antimicrobial and antioxidant compounds, as revealed by chromatographic analysis. BR-2 latex was found to have significant antioxidant activity (75%) followed by S-146 (64.6%) and AR-14 (52.9%). The maximum antimicrobial activity was found in BR-2 latex compared to other tested latex varieties. The results of this investigation showed that mulberry latex from the BR-2 type may successfully control both bacterial and fungal infections, with the added benefit of having enhanced antioxidant capabilities., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

The entry of the severe acute respiratory syndrome coronavirus 2 virus in human cells is mediated by the binding of its surface spike protein to the human angiotensin-converting enzyme 2 (ACE2) receptor. A 23-residue long helical segment (SBP1) at the binding interface of human ACE2 interacts with viral spike protein and therefore has generated considerable interest as a recognition element for virus detection. Unfortunately, emerging reports indicate that the affinity of SBP1 to the receptor-binding domain of the spike protein is much lower than that of the ACE2 receptor itself. Here, we examine the biophysical properties of SBP1 to reveal factors leading to its low affinity for the spike protein. Whereas SBP1 shows good solubility (solubility > 0.8 mM), circular dichroism spectroscopy shows that it is mostly disordered with some antiparallel β-sheet content and no helicity. The helicity is substantial (>20%) only upon adding high concentrations (≥20% v/v) of 2,2,2-trifluoroethanol, a helix promoter. Fluorescence correlation spectroscopy and single-molecule photobleaching studies show that the peptide oligomerizes at concentrations >50 nM. We hypothesized that mutating the hydrophobic residues (F28, F32, and F40) of SBP1, which do not directly interact with the spike protein, to alanine would reduce peptide oligomerization without affecting its spike binding affinity. Whereas the mutant peptide (SBP1 mod ) shows substantially reduced oligomerization propensity, it does not show improved helicity. Our study shows that the failure of efforts, so far, to produce a short SBP1 mimic with a high affinity for the spike protein is not only due to the lack of helicity but is also due to the heretofore unrecognized problem of oligomerization., (Copyright © 2021 Biophysical Society. Published by Elsevier Inc. All rights reserved.)

Cyclin-dependent kinase 1 (CDK1) is essential for cell-cycle progression. While dependence of CDK activity on cyclin levels is well established, molecular mechanisms that regulate their binding are less understood. Here, we report for the first time that CDK1:cyclin-B binding is not default but rather determined by the evolutionarily conserved catalytic residue, lysine-33 in CDK1. We demonstrate that the charge state of this lysine allosterically remodels the CDK1:cyclin-B interface. Cell cycle-dependent acetylation of lysine-33 or its mutation to glutamine, which mimics acetylation, abrogates cyclin-B binding. Using biochemical approaches and atomistic molecular dynamics simulations, we have uncovered both short-range and long-range effects of perturbing the charged state of the catalytic lysine, which lead to inhibition of kinase activity. Specifically, although loss of the charge state of catalytic lysine did not impact ATP binding significantly, it altered its orientation in the active site. In addition, the catalytic lysine also acts as an intra-molecular electrostatic tether at the active site to orient structural elements interfacing with cyclin-B. Physiologically, opposing activities of SIRT1 and P300 regulate acetylation and thus control the charge state of lysine-33. Importantly, cells expressing acetylation mimic mutant of Cdc2/CDK1 in yeast are arrested in G2 and fail to divide, indicating the requirement of the deacetylated state of the catalytic lysine for cell division. Thus, by illustrating the molecular role of the catalytic lysine and cell cycle-dependent deacetylation as a determinant of CDK1:cyclin-B interaction, our results redefine the current model of CDK1 activation and cell-cycle progression., (Copyright © 2019 Elsevier Ltd. All rights reserved.)