Joanna Bojarska

Short peptidomimetics are compact, conformationally restricted scaffolds for relating structural changes to molecular recognition, while CF ₃ substitution is widely used to tune physicochemical properties and ligand–environment complementarity.

Conformational lability in short peptides can, under defined conditions, be translated into reproducible conformational control in crystal structures.

Aim: This paper presents a comprehensive analysis of the gender pay gap (GPG) in Poland, examined within the national, European, and global contexts. It explores key causes, sectoral disparities, and the broader economic and policy implications. Particular emphasis is placed on the adjusted gender pay gap (GPG), which provides a more accurate measure by controlling for variables such as education, experience, and job position. This method reveals deeper and more persistent wage disparities than those suggested by the unadjusted GPG. Methodology/Data sources: The study adopts a narrative literature review approach supported by secondary data analysis. It draws upon a wide range of national and international data sources, including Eurostat, Poland’s Central Statistical Office (GUS), OECD, and various EU and global reports published between 2015 and 2025. Findings: In 2023, the unadjusted GPG in the EU was 12%, while in Poland it stood at 7.8%. Despite appearing relatively low, Poland’s GPG has stagnated or worsened over the past decade, while the EU has seen a gradual decline. The adjusted GPG – reflecting education, experience, and job type – was 11.4% for the EU and 12.5% for Poland (as of 2018). Sectoral differences in Poland are striking: 24.8% in information and communication and 27.6% in finance and insurance. Misinterpretation of unadjusted vs. adjusted data may distort the public debate and policy response. Conclusions: The GPG remains a persistent challenge in both the EU and Poland. The lack of clarity between adjusted and unadjusted measures risks underestimating systemic inequality. Effective implementation of recent EU regulations, such as the Pay Transparency and Work-Life Balance Directives, will be key to narrowing the gap. Significance/Originality: This is, to our knowledge, the first holistic synthesis of various GPG indicators for Poland, presented alongside EU and global comparisons. The findings underscore the importance of integrated, data-informed policies to advance gender equality as a cornerstone of sustainable development. Cel: W artykule przedstawiamy kompleksową analizę luki płacowej ze względu na płeć (GPG) w Polsce, uwzględniając kontekst krajowy, europejski i globalny. Omawiamy główne przyczyny, różnice sektorowe oraz szersze konsekwencje gospodarcze i społeczne. Szczególny nacisk kładziemy na skorygowaną lukę płacową ze względu na płeć (adjusted GPG), która stanowi dokładniejszy miernik, ponieważ uwzględnia zmienne takie jak wykształcenie, doświadczenie zawodowe oraz zajmowane stanowisko. Metoda ta ujawnia głębsze i trwalsze nierówności płacowe niż te wskazywane przez nieskorygowaną lukę płacową (unadjusted GPG). Metodologia/Źródła danych: Badanie ma charakter narracyjnego przeglądu literatury, wspartego analizą danych wtórnych. Wykorzystaliśmy szeroki zakres źródeł krajowych i międzynarodowych, m.in. Eurostat, GUS, OECD oraz raporty UE i organizacji globalnych z lat 2015–2025. Główne wyniki: W 2023 r. niezrównana (niekorygowana) luka płacowa w UE wynosiła 12%, a w Polsce 7,8%. Choć ten wynik wydaje się korzystny, GPG w Polsce nie ulega poprawie od dekady, w przeciwieństwie do trendów unijnych. Skorygowana GPG (uwzględniająca m.in. wykształcenie, doświadczenie i stanowisko) wynosiła 11,4% w UE i 12,5% w Polsce (dane z 2018 r.). W niektórych sektorach w Polsce różnice są znacznie wyższe: np. 24,8% w sektorze informacji i komunikacji czy 27,6% w finansach. Niezrozumienie różnicy między danymi korygowanymi i niekorygowanymi może prowadzić do błędnych wniosków. Wnioski: Luka płacowa nadal stanowi poważne wyzwanie – zarówno w Polsce, jak i w UE. Klarowne rozróżnienie między metodami pomiaru (GPG skorygowana vs. niekorygowana) jest kluczowe dla skutecznych działań. Nowe regulacje UE, jeśli zostaną właściwie wdrożone, mogą pomóc w zmniejszeniu GPG. Znaczenie/Oryginalność: To, według naszej wiedzy, pierwsza tak kompleksowa synteza różnych wskaźników GPG dla Polski w porównaniu z kontekstem unijnym i globalnym. Wyniki podkreślają potrzebę zintegrowanych, opartych na dokładnych danych działań na rzecz równości płci jako warunku zrównoważonego rozwoju.

Four benzyltrimethylammonium (BTMA) salts were successfully prepared: bis(benzyltrimethylammonium) hexachloroplatinate (1), benzyltrimethylammonium tetrachloroaurate (2), bis(benzyltrimethylammonium) tetrachlorocuprate (3), and bis(benzyltrimethylammonium) tetrabromocuprate (4) from benzyltrimethylammonium hydroxide (Triton B). Their crystal structures were determined by single-crystal X-ray diffraction, and the supramolecular architectures were characterized hierarchically. Extended Hirshfeld surface analysis, including enrichment ratio calculations, was performed to evaluate intermolecular interactions. Nonclassical hydrogen bonds, such as C–H^…Cl(Br), involving the anions, contribute to the formation of self-assembled architectures. Additional stabilization arises from π^…π and Cu–Br^…π interactions, particularly in crystals 2 and 4, respectively. Hirshfeld surface analysis showed that H^…H and C^…H/H^…C interactions are the dominant contributors in all crystals. According to enrichment ratio calculations, C^…H/H^…C interactions in 1, 3, and 4; Cl^…H/H^…Cl in 1 and 3; Cu^…H/H^…Cu in 3 and 4; and Br^…H/H^…Br and Br^…C/C^…Br in 4 are statistically favored in the crystal packing. Halogen bonding Cl^…Cl was observed in 1 but does not significantly influence packing. Energy framework calculations indicated that dispersive interactions are favorable in the analyzed crystals. A library of H-bonding supramolecular patterns, including interchangeable synthons, is provided and may guide the rational design of new derivatives with controllable features. Finally, the topology of intermolecular connections and the electronic structure of the benzyltrimethylammonium cation, investigated by quantum-chemical calculations, provide insights into its reactivity.

This study presents the synthesis and comprehensive characterization of a novel, modified ultra-short peptide, Ac-Phe-Aib-Deg-OH ( N -acetyl- L -phenylalanyl-α-aminoisobutyryl - α,α-diethylglycine), ( 1 ), highlighting its potential as an anticancer ligand for G protein-coupled receptors (GPCRs). The structure of the compound was elucidated using single-crystal X-ray crystallography, revealing its pseudo-macrocyclic nature. Hydrogen bonds and dispersion forces drive the hierarchical supramolecular self-assembly of ( 1 ). A comparative analysis with structurally similar structures, that is, achatin derived from the Cambridge Structural Database, was conducted using diverse in silico methods. A detailed analysis of intra- and intermolecular interactions in the structures, especially using modern structural database-driven techniques, provides further insight into the preferential bonding mode of ( 1 ) as a potential drug candidate. Density functional theory calculations were performed to rationalize the interactions and reactivity of the molecules. To validate the predicted anticancer activity of the analysed molecules, we evaluated the binding affinities of these molecules to cancer-related GPCRs. We examined the interaction maps using molecular docking analysis with targets associated with various types of cancer. These findings suggest that ( 1 ) could be a promising candidate for future studies on designing innovative pseudo-macrocyclic ultra-short peptides containing unnatural amino acids for new targeted anticancer therapy.

G-protein-coupled receptors (GPCRs) are vital transmembrane proteins that regulate a wide range of physiological processes by transmitting extracellular signals into intracellular responses. Among them, the β2-adrenergic receptor (β2-AR) plays a central role in bronchodilation, smooth muscle relaxation, and cardiovascular modulation, making it a key therapeutic target for diseases such as asthma, chronic obstructive pulmonary disease (COPD), and hypertension. This study explores the potential of natural bioactive compounds like ephedrine, quercetin, catechin, and resveratrol as alternative ligands for β2-AR through molecular docking analysis. Using AutoDock 4.6, these compounds were docked with the binding site of the β2-AR (PDB ID: 2RH1), and their binding affinities and interaction map were evaluated. Results showed that all compounds exhibited favorable binding energies and stable interactions with key receptor residues, with quercetin demonstrating the highest affinity. The findings suggest that these natural compounds may serve as promising leads for the development of safer, plant-derived modulators of β2-AR, supporting the role of computational approaches in natural product-based drug discovery. However, as docking cannot determine functional activity, these findings should be interpreted as preliminary and require experimental validation.

G-protein-coupled receptors (GPCRs) are a group of various membrane proteins that mediate essential physiological processes by translating extracellular signals into intracellular responses. The β2-Adrenergic Receptor (β2-AR), a key GPCR, plays a critical role in smooth muscle relaxation, bronchodilation, and cardiovascular function, making it an important therapeutic target for diseases such as asthma and hypertension. Diketopiperazines (DPKs), as cyclic peptides, have shown promise as scaffolds for inhibiting protein interactions and modulating receptor activity, offering a potential alternative to traditional small-molecule inhibitors with reduced side effects. In this study, five DPK derivatives were selected from the PubChem database and evaluated for their binding affinity to the 3D structure of β2-AR (PDB ID = 2RH1) through molecular docking studies using AutoDock 4.6 and MGLTools. The binding energy and hydrogen bond formation of each compound were evaluated to determine their interaction efficiency. Among the compounds, tryptophan-proline diketopiperazine (compound 3) exhibited the highest binding affinity with a binding energy of −5.89 kcal/mol. This enhanced interaction is attributed to the aromatic nature of tryptophan, which promotes strong π-π stacking interactions, and the rigidity of proline, which optimally fits within the receptor’s binding pocket. Hydrophobic interactions further stabilized the complex. These findings highlight compound 3 as a promising β2-AR modulator, providing valuable insights for the design of peptide-based inhibitors targeting β2-AR-related pathologies.

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Among other applications, they have been employed to detect, prevent, and treat infectious diseases. Peptides are used in diagnostic applications, imitating the molecular recognition properties of proteins for the detection of bacterial or viral infections, as antibiotics mimicking the function of natural antimicrobial peptides, and as crucial vaccine antigenic components and immunostimulators, to name a few applications. They are a very promising platform for drug and vaccine development (Skwarczynski and Toth, 2016;Wang and Li,2023). Nevertheless, peptides do have certain limitationsthey are easily biodegradable, break all Lipinski's rules, lack oral activity, and peptide antigens exhibit poor immunogenicity (Apostolopoulos et al., 2021;Apostolopoulos et al., 2022;Bucci et al., 2021). Thus, various strategies have been developed to overcome these shortcomings by structural modification or utilization of specialized formulations. This Research Topic, aimed to provide a forum for new studies and discussions on novel concepts, mechanisms, and applications in the field of peptide-based detection, prevention, and treatment of infectious diseases. It includes five original articles, one brief research report, and one review paper.Li et al. conducted a comprehensive review of the current research progress in the development and application of polyethylene glycol (PEG)-based therapeutic proteins and peptides. The authors discussed either the physicochemical properties or classification of PEG derivatives, keeping in mind the prospects of PEGylated peptides. In addition, they show opportunities for further innovations in this area.Cationic ultrashort lipopeptides are promising agents to fight multidrug-resistant bacteria. Hernández-Ortiz et al. demonstrated that anionic and neutral zwitterionic tripeptides exhibit antimicrobial and membrane-disrupting effects against inter alia Streptococcus pneumoniae and Streptococcus pyogenes. For their experiment, the researchers utilized newly designed C-terminal lipidated tripeptides with specific features (net charges ranging from -2 to +1) and a fatty amine conjugated to the C-terminal. Thus, the authors presented lipopeptides as appealing antimicrobial candidates with enhanced bioactivity and reduced toxicity for potential use in medical applications.Candida species are fungus species that have the ability to form biofilms that contribute to their pathogenicity and provide protection against antifungal drugs. Among these species, Candida glabrata is a prevalent yeast responsible for infections in humans, and is known for its ability to form biofilms. Madhuri et al. evaluated the combined effects of two highly promising naturally occurring antifungal lipopeptides named AF4 and AF5. They reported that these peptides exhibited an enhanced in vitro anti-biofilm effect when used alone or in combination with fluconazole.Melittin, an antimicrobial peptide derived from bee venom, is generally considered toxic and consequently lacks clinical utility. Nevertheless, modifications on its amino acid sequence through cyclization, dimerization, or truncation have been shown to reduce its toxicity. Matthyssen et al. substituted the three lysine residues with lysine homologs containing shorter side chains (such as ornithine, diaminobutyric acid, and diaminopropanoic acid) and dimerized melittin. They observed improved antimicrobial activity against Gram-negative bacteria, but no significant improvement in activity against Gram-positive bacteria. On the other hand, toxicity toward HEK293 and H4IIE cells was only slightly reduced. Furthermore, researchers suggested that more drastic modifications as well as encapsulation in nanocarriers, conjugation to other substances, and synergistic effects of melittin with antibiotics have the potential to reduce the effective dose of melittin to non-toxic levels.Acinetobacter baumanni is a highly drug-resistant pathogen, posing significant challenges in clinical treatment. Meng et al. conducted an evaluation of the synergistic antibacterial activity and additive effects of peptide antibiotics in combination with other antimicrobial agents against A. baumanni in both planktonic and biofilm forms in vitro. More specifically, the combination of polymyxins B and E together with imipenem act synergistically, while polymyxin E with rifampicin and bacitracin with imipenem or meropenem demonstrated additive effects against bacteria in planctonic form. In antibiofilm activity, synergistic activity was observed for combination of polymyxin B and E with azithromycin, while additive effect was confirmed for mixture of teicoplanin with tigecycline or rifampicin. The use of polymyxins along with carbapenems or azithromycin was suggested to represent an optimal therapeutic approach for A. baumannii infections.Suppressive antibiotic therapy is a valuable strategy to reduce infection progression in situations where alternative therapeutic approaches are not viable. The 15 years old lipoglycopeptide antibiotic, dalbavancin, exhibits a prolonged half-life and allows for less frequent dosing. Ruiz-Sancho et al. present their multicenter real-life clinical experience across multicenters highlighting the efficacy of dalbavancin-based approach in suppressive antibiotic therapy for prosthetic joint or vascular infections. Their findings provide valuable insights to support further evaluation of this treatment modality in patients with prosthetic infections in the outpatient setting when other methods are not feasible.Thanatin, a cyclic analog of a beta-hairpin antimicrobial peptide, has diverse antibacterial and antifungal activities. It forms transmembrane pores and inhibits outer membrane biogenesis by binding to the LptA protein of Escherichia coli and blocking lipopolysaccharide transport. Notably, thanatin acts in synergy with antibiotic polymyxin B. Shepperson et al. developed thanatin analogs in which labile disulfide was replaced with...