52 research outputs found
Antifungális ciklusos lipodepszipeptidek membránra kifejtett hatásának vizsgálata = Investigation of cyclic lipodepsipeptides-membrane interactions
A Pseudomonas Syringae pv. Syringae növĂ©nyi kĂłrokozĂł baktĂ©rium törzs ciklusos lipopeptideket (CLPs) termel, amelyek eltĂ©rĹ‘ hatásspektruma, antimikrobiális Ă©s patogĂ©n aktivitása szerkezeti kĂĽlönbözĹ‘sĂ©gĂĽk fĂĽggvĂ©nye, ezĂ©rt a CLP molekulák biolĂłgiai aktivitásának megĂ©rtĂ©sĂ©hez szerkezetĂĽk molekuláris szintű megismerĂ©se szĂĽksĂ©ges. A posztdoktori munkám a syringomycin-E, a syringotoxin-B Ă©s a syringopeptin-25A vegyĂĽlet, hatásmechanizmusának molekula dinamikai szimuláciĂłval törtĂ©nĹ‘ vizsgálatára irányult. A projektet három lĂ©pĂ©sbe valĂłsĂtottam meg: a CLP molekulák háromdimenziĂłs szerkezetĂ©nek meghatározását Ă©s jellemzĂ©sĂ©t hidrofil Ă©s hidrofĂłb közegben, a sejtmembránt modellezĹ‘ lipid kettĹ‘srĂ©tegek megĂ©pĂtĂ©se követte, majd a peptid-lipid rendszerek összeĂ©pĂtĂ©sĂ©t, hosszĂş távĂş molekula dinamikai szimuláciĂłját Ă©s annak analĂzisĂ©t vĂ©geztem el. A trajektĂłriák rĂ©szletes analĂzisĂ©vel rámutattam, hogy a szimulált konformerek szerkezete (kĂsĂ©rleti NOE-NMR Ă©rtĂ©keket beĂ©pĂtĂ©sĂ©vel) összhangban van a kĂsĂ©rleti eredmĂ©nyek alapján valĂłszĂnűsĂtett szerkezetekkel. A peptid-lipid rendszerek elemzĂ©sĂ©vel meghatároztam a peptid Ă©s a lipid szerkezetĂ©ben bekövetkezĹ‘ molekuláris szintű változásokat. Rámutattam azon aminosavakra, amelyek rĂ©szt vesznek a peptid molekulák szerkezeti stabilitásában. Továbbá meghatároztam, a peptideknek a lipid kettĹ‘srĂ©tegbe törtĂ©nĹ‘ beĂ©pĂĽlĂ©sĂ©t, alakĂtva annak szerkezetĂ©t, Ă©s feltártam a peptid Ă©s a lipid molekulák között kialakulĂł kölcsönhatásokat. | In our work we investigated in atomic detail the molecular features of three main antifungal cyclic lipodepsipeptides in hydrophilic, hydrophobic and lipid bilayer environments by molecular dynamics simulation. As a first step we built a model of the peptides and examined their structures in water and octane using GROMACS in 200 ns MD simulations including experimental NMR NOE data. We determined structural preferences and conformational flexibility of CLPs in both solvents, in particular the importance of side-chain interactions in the peptide stability. The obtained three-dimensional structures were used for further investigation of the CLP-lipid bilayers interactions. The trajectory analyses of the peptide-lipid systems reveal the atomistic structural modifications of peptide and lipid molecules. It was point out the role of peptide residues which are involved in structural stabilization effects of peptides. We determined the mode of insertion of peptides into lipid bilayers, and the structural perturbations of lipids. Furthermore, we find out the peptide-peptide and peptide-lipid interactions
Generalized elimination of the global translation from explicitly correlated Gaussian functions
This paper presents the multi-channel generalization of the center-of-mass
kinetic energy elimination approach [Mol. Phys., 111 2086 (2013)] when the
Schr\"odinger equation is solved variationally with explicitly correlated
Gaussian functions. The approach has immediate relevance in many-particle
systems which are handled without the Born--Oppenheimer approximation and can
be employed also for Dirac-type Hamiltonians. The practical realization and
numerical properties of solving the Schr\"odinger equation in laboratory-frame
Cartesian coordinates are demonstrated for the ground rovibronic state of the
H ion and the
H molecule.Comment: 24 pages, 1 figure, 2 table
Relativistic two-electron atomic and molecular energies using coupling and double groups: role of the triplet contributions to singlet states
The triplet contribution is computed to the 1 and 2 states
of the He atom, to the state of the Li and Be
ions, and to the ground state of the H molecule by
extensive use of double-group symmetry (equivalent to coupling for the
atomic systems) during the course of the variational solution of the no-pair
Dirac-Coulomb-Breit wave equation. The no-pair Dirac-Coulomb-Breit energies are
converged within a sub-parts-per-billion relative precision using an explicitly
correlated Gaussian basis optimized to the non-relativistic energies. The
fine-structure constant dependence of the triplet sector contribution
to the variational energy is at leading order, in
agreement with the formal perturbation theory result available from the
literature
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