Background: Cyclodextrins (CDs) in combination with therapeutic proteins and other bioactive compounds have been proposed as candidates that show enhanced chemical and enzymatic stability, better absorption, slower plasma clearance and improved dose–response curves or immunogenicity. As a result, an important number of therapeutic complexes between cyclodextrins and bioactive compounds capable to control several diseases have been developed. Results: In this article, the synthesis and the structural study of a conjugate between a luteinizing hormone-releasing hormone (LHRH) analogue, related to the treatment of hormone dependent cancer and fertility, and modified β-cyclodextrin residue are presented. The results show that both the phenyl group of tyrosine (Tyr) as well as the indole group of tryptophan (Trp) can be encapsulated inside the cyclodextrin cavity. Solution NMR experiments provide evidence that these interactions take place intramolecularly and not intermolecularly. Conclusions: The study of a LHRH analogue conjugated with modified β-cyclodextrin via high field NMR and MD experiments revealed the existence of intramolecular interactions that could lead to an improved drug delivery. General significance: NMR in combination with MD simulation is of great value for a successful rational design of peptide–cyclodextrin conjugates showing stability against enzymatic proteolysis and a better pharmacological profile.
COBISS.SI-ID: 5596698
The human mitochondrial voltage-dependent anion channel (VDAC) is a large transmembrane β – barrel protein, whose N-terminal helical fragments partially closes the pore and thus controls the exchange the ions and metabolites. We studied the folding propensity of three different N-terminal fragments found in high eukaryotes. By using various spectroscopies techniques and theoretical computer-assisted approaches, we have characterised their conformational equilibriums. Significant differences have been found in the intrinsic helical propensity of the three peptides decreasing in the following order hVDAC2) hVDAC3) hVDAC1. Our results suggest the different chemo-physical properties of the N-terminal domains are correlated to the different functions for the three isomers.
COBISS.SI-ID: 5824794
Bacterial resistance to the available antibiotic agents underlines an urgent need for the discovery of novel antibacterial agents. Members of the bacterial Mur ligase family MurC–MurF involved in the intracellular stages of the bacterial peptidoglycan biosynthesis have recently emerged as a collection of attractive targets for novel antibacterial drug design. In this study, we have first extended the knowledge of the class of furan-based benzene-1,3-dicarboxylic acid derivatives by first showing a multiple MurC–MurF ligase inhibition for representatives of the extended series of this class. Steady-state kinetics studies on the MurD enzyme were performed for compound 1, suggesting a competitive inhibition with respect to ATP. To the best of our knowledge, compound 1 represents the first ATP-competitive MurD inhibitor reported to date with concurrent multiple inhibition of all four Mur ligases (MurC–MurF). Subsequent molecular dynamic (MD) simulations coupled with interaction energy calculations were performed for two alternative in silico models of compound 1 in the UMA/d-Glu- and ATP-binding sites of MurD, identifying binding in the ATP-binding site as energetically more favorable in comparison to the UMA/d-Glu-binding site, which was in agreement with steady-state kinetic data. In the final stage, based on the obtained MD data novel furan-based benzene monocarboxylic acid derivatives 8–11, exhibiting multiple Mur ligase (MurC–MurF) inhibition with predominantly superior ligase inhibition over the original series, were discovered and for compound 10 it was shown to possess promising antibacterial activity against S. aureus. These compounds represent novel leads that could by further optimization pave the way to novel antibacterial agents.
COBISS.SI-ID: 5677082
An anti-inflammatory complex of Ag(I), namely [Ag(tpp)3(asp)](dmf) [tpp = triphenylphosphine, aspH = aspirin, dmf = N,N-dimethylformamide], was synthesized in an attempt to develop novel metallotherapeutic molecules. STD 1H NMR experiments were used to examine if this complex binds to LOX-1. The 1H NMR spectra in buffer Tris/D2O betrayed the existence of two complexes: the complex of aspirin and the complex of salicylic acid produced after deacetylation of aspirin. Nevertheless, the STD spectra showed that only the complex of salicylic acid is bound to the enzyme. Molecular docking and dynamics were used to complement our study. The complexes were stabilized inside a large LOX-1 cavity by establishing a network of hydrogen bonds and steric interactions. The complex formation with salicylic acid was more favorable. The in silico results provide a plausible explanation of the experimental results, which showed that only the complex with salicylic acid enters the binding cavity.
COBISS.SI-ID: 5737498