A Fragmenting Protocol with Explicit Hydration for Calculation of Binding Enthalpies of Target-Ligand Complexes at a Quantum Mechanical Level

Optimization of the enthalpy component of binding thermodynamics of drug candidates is a successful pathway of rational molecular design. However, the large size and missing hydration structure of target-ligand complexes often hinder such optimizations with quantum mechanical (QM) methods. At the same time, QM calculations are often necessitated for proper handling of electronic effects. To overcome the above problems, and help the QM design of new drugs, a protocol is introduced for atomic level determination of hydration structure and extraction of structures of target-ligand complex interfaces. The protocol is a combination of a previously published program MobyWat, an engine for assigning explicit water positions, and Fragmenter, a new tool for optimal fragmentation of protein targets. The protocol fostered a series of fast calculations of ligand binding enthalpies at the semi-empirical QM level. Ligands of diverse chemistry ranging from small aromatic compounds up to a large peptide helix of a molecular weight of 3000 targeting a leukemia protein were selected for systematic investigations. Comparison of various combinations of implicit and explicit water models demonstrated that the presence of accurately predicted explicit water molecules in the complex interface considerably improved the agreement with experimental results. A single scaling factor was derived for conversion of QM reaction heats into binding enthalpy values. The factor links molecular structure with binding thermodynamics via QM calculations. The new protocol and scaling factor will help automated optimization of binding enthalpy in future molecular design projects

Quantitative Analysis of Qualitative Data: Using Voyant Tools to Investigate the Sales-Marketing Interface

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Sculpting the beta-peptide foldamer H12 helix via a designed side-chain shape

The long-range side-chain repulsion between the (1R, 2R, 3R, 5R)-2- amino-6,6-dimethyl-bicyclo[3.1.1]-heptane-3-carboxylic acid (trans-ABHC) residues stabilize the H12 helix in beta-peptide oligomers

Structural Adaptation of the Single-Stranded DNA-Binding Protein C-Terminal to DNA Metabolizing Partners Guides Inhibitor Design

Single-stranded DNA-binding protein (SSB) is a bacterial interaction hub and an appealing target for antimicrobial therapy. Understanding the structural adaptation of the disordered SSB C-terminus (SSB-Ct) to DNA metabolizing enzymes (e.g., ExoI and RecO) is essential for designing high-affinity SSB mimetic inhibitors. Molecular dynamics simulations revealed the transient interactions of SSB-Ct with two hot spots on ExoI and RecO. The residual flexibility of the peptide–protein complexes allows adaptive molecular recognition. Scanning with non-canonical amino acids revealed that modifications at both termini of SSB-Ct could increase the affinity, supporting the two-hot-spot binding model. Combining unnatural amino acid substitutions on both segments of the peptide resulted in enthalpy-enhanced affinity, accompanied by enthalpy–entropy compensation, as determined by isothermal calorimetry. NMR data and molecular modeling confirmed the reduced flexibility of the improved affinity complexes. Our results highlight that the SSB-Ct mimetics bind to the DNA metabolizing targets through the hot spots, interacting with both of segments of the ligands

Rationally designed foldameric adjuvants enhance antibiotic efficacy via promoting membrane hyperpolarization

The negative membrane potential of bacterial cells influences crucial cellular processes. Inspired by the molecular scaffold of the antimicrobial peptide PGLa, we have developed antimicrobial foldamers with a computer-guided design strategy. The novel PGLa analogues induce sustained membrane hyperpolarization. When co-administered as an adjuvant, the resulting compounds - PGLb1 and PGLb2 - have substantially reduced the level of antibiotic resistance of multi-drug resistant Escherichia coli, Klebsiella pneumoniae and Shigella flexneri clinical isolates. The observed antibiotic potentiation was mediated by hyperpolarization of the bacterial membrane caused by the alteration of cellular ion transport. Specifically, PGLb1 and PGLb2 are selective ionophores that enhance the Goldman-Hodgkin-Katz potential across the bacterial membrane. These findings indicate that manipulating bacterial membrane electrophysiology could be a valuable tool to overcome antimicrobial resistance

Comparison of immune activation of the COVID vaccines : ChAdOx1, BNT162b2, mRNA-1273, BBIBP-CorV, and Gam-COVID-Vac from serological human samples in Hungary showed higher protection after mRNA-based

To gain insight into the different protective mechanisms of approved vaccines, this study focuses on the comparison of humoral and cellular immune responses of five widely used vaccines including ChAdOx1 (AZD1222, AstraZeneca), BNT162b2 (Pfizer), mRNA-1273 (Moderna), BBIBP-CorV (Sinopharm), and Gam-COVID-Vac (Sputnik V).Isolated plasma from 95 volunteers' blood samples was used to measure anti-SARS-CoV-2 humoral and cellular immune responses. Positive controls were recovered patients from COVID-19 (unvaccinated). Specific quantification kits for anti-nucleocapsid IgG, anti-Spike protein IgG, neutralizing antibodies as well as specific SARS-CoV-2 antigens for T-cell activation were used and Spearman correlation and matrix analyses were performed to compare overall immune responses.Nucleocapsid antibodies were significantly higher for the BBIBP-CorV and convalescent group when compared to other vaccines. In contrast, subjects vaccinated with BNT162b2 and mRNA-1273 presented significantly higher anti-spike IgG. In fact, 9.1% of convalescent, 4.5% of Gam-COVID-Vac, 28.6% of ChAdOx1, and 12.5% of BBIBP-CorV volunteers did not generate anti-spike IgG. Similarly, a positive correlation was observed after the neutralization assay. T-cell activation studies showed that mRNA-based vaccines induced a T-cell driven immune response in all cases, while 55% of convalescents, 8% of BNT162b1, 12,5% of mRNA-1273, 9% of Gam-COVID-Vac, 57% of ChAdOx1, and 56% of BBIBP-CorV subjects presented no cellular response. Further correlation matrix analyses indicated that anti-spike IgG and neutralizing antibodies production, and T-cell activation follow the same trend after immunization.RNA-based vaccines induced the most robust adaptive immune activation against SARS-CoV-2 by promoting a significantly higher T-cell response, anti-spike IgG and neutralization levels. Vector-based vaccines protected against the virus at a comparable level to convalescent patients

A fehérje-fehérje kölcsönhatások szerkezeti alapjai és biológiai szerepük: multidiszciplináris megközelítés = The structural basis and biological role of protein-protein interactions: a multidisciplinary approach

Az ELTE Biokémiai Tanszék tudományos kutatásainak tengelyében évtizedek óta a fehérjék szerkezetének, funkciójának és a fehérjék közötti kölcsönhatások szerkezeti hátterének és biológiai jelentőségének felderítése áll. Valamennyi, az elmúlt négyéves pályázati ciklusban vállalt feladatunk teljesítése a fenti célokat szolgálta. A vezető kutató megítélése szerint a pályázat támogatásával elért legkiemelkedőbb eredményeink, a vállalt témák sorrendjében a következők voltak: 1) Megállapítottuk, hogy a primata-specifikus tripszin 4 egyik, feltehetően biológiai szubsztrátja a mielin bázikus fehérje és modellt dolgoztunk ki a humán tripszinogén 4 asztroglia sejteken belüli transzportjának és aktivációjának követésére 2) Hazánkban elsőként állítottuk be a fágbemutatás módszerét, melynek segítségével az eredetitől eltérő specifitású proteáz inhibitorokat állítottunk elő. 3) Megállapítottuk, hogy a miozin II motorfehérje regulációs képességének az az előfeltétele, hogy aproximális kétláncú coiled-coil szerkezet instabil legyen. 4) Felderítettük a miozin II specifikus inhibitorának, a blebbistatinnak a működésmechanizmusát. 5) Kifejlesztettünk egy új tranziens kinetikai módszert, a ?temperature-jump/stopped flow-t a módszer alkalmazásához szükséges berendezéssel együtt. | For decades the focus of scientific interest of the Biochemistry Department, Eötvös Loránd University, Budapest has been the investigation of the structural basis and biological significance of protein-protein interactions. Our research efforts during the last 4 years were to achieve specific goals along this line. In the view of the principal investigator of this grant the most outstanding scientific results achieved, or discoveries made by using the financial means of the grant are as follows: 1) We provided indirect evidence that one of the potential pathological substrate of human trypsin 4 might be myelin basic protein. Furthermore, we worked out a model to follow the transport and activation of human trypsinogen 4 within human astroglia cells. 2) For the first time in Hungary we introduced the methodology of phage-display in our department and by using this method we succeeded in producing serine protease inhibitors with altered specificity. 3) Evidence was provided that the instability of the proximal two-chain coiled structure in myosin II plays an important regulatory role in the myosin functioning 4) The mechanism of action of the inhibitor of myosin II, blebbistatin was explored. 5) We developed and set up a new method and apparatus to perform ?temperature-jump/stopped flow? transient kinetics experiments

Rationally Designed Foldameric Adjuvants Enhance Antibiotic Efficacy via Promoting Membrane Hyperpolarization

The negative membrane potential of bacterial cells influences crucial cellular processes. Inspired by the molecular scaffold of the antimicrobial peptide PGLa, we have developed antimicrobial foldamers with a computer-guided design strategy. The novel PGLa analogues induce sustained membrane hyperpolarization. When co-administered as an adjuvant, the resulting compounds – PGLb1 and PGLb2 – have substantially reduced the level of antibiotic resistance of multi-drug resistant Escherichia coli, Klebsiella pneumoniae and Shigella flexneri clinical isolates. The observed antibiotic potentiation was mediated by hyperpolarization of the bacterial membrane caused by the alteration of cellular ion transport. Specifically, PGLb1 and PGLb2 are selective ionophores that enhance the Goldman–Hodgkin–Katz potential across the bacterial membrane. These findings indicate that manipulating bacterial membrane electrophysiology could be a valuable tool to overcome antimicrobial resistance