Sökning: "QM MM"

Visar resultat 1 - 5 av 25 avhandlingar innehållade orden QM MM.

  1. 1. QM/MM free-energy perturbation and other methods to estimate ligand-binding affinities

    Författare :Martin Olsson; Beräkningskemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Computer-aided drug design; protein–ligand binding; molecular dynamics; free-energy perturbation; QM MM; convergence;

    Sammanfattning : Experimental drug discovery is very time-consuming, risky and comes at a huge cost, typically several billion USD per drug. Even though decades of experimental drug discovery have provided cures of many diseases, there are still diseases for which there is no effective drug available. LÄS MER

  3. 2. 5-Aminolevulinic acid and derivatives thereof : properties, lipid permeability and enzymatic reactions

    Författare :Edvin Erdtman; Leif Eriksson; Tore Brinck; Örebro universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; 5-Aminolevulinic acid; tautomerization; PDT; DFT; MM; QM MM; Porphobilinogen synthase; Uroporphyrinogen III decarboxylase; membrane penetration; enzyme mechanism; Biophysical chemistry; Biofysikalisk kemi; Quantum chemistry; Kvantkemi; Theoretical chemistry; Teoretisk kemi; Fysikalisk kemi; Physical Chemistry; Biochemistry; Biokemi;

    Sammanfattning : 5-aminolevulinic acid (5-ALA) and derivatives thereof are widely usedprodrugs in treatment of pre-malignant skin diseases of the cancer treatmentmethod photodynamic therapy (PDT). The target molecule in 5-ALAPDTis protoporphyrin IX (PpIX), which is synthesized endogenously from5-ALA via the heme pathway in the cell. LÄS MER

  4. 3. Reaction mechanism of metalloenzymes studied by theoretical methods

    Författare :Geng Dong; Beräkningskemi; []
    Nyckelord :Metalloenzymes; Reaction mechanism; QM MM; DFT; DMRG; CAS-srDFT; Big-QM; QTCP;

    Sammanfattning : Metalloenzymes catalyse a wide variety of reactions in nature. In the thesis, I have studied the reaction mechanism of three metalloenzymes, viz. LÄS MER

  5. 4. Calculations of accurate energies in proteins with QM/MM methods

    Författare :Jimmy Heimdal; Beräkningskemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Accurate calculation of energies for protein reactions is a hard problem. There are many reasons for wanting to calculate these energies, e.g. ligand design and the study of enzyme reactions. LÄS MER

  7. 5. Quantum and quantum-classical calculations of core-ionized molecules in varied environments

    Författare :Tuomas Löytynoja; Hans Ågren; Jukka Tulkki; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Electron spectroscopy; UPS; XPS; photodissociation; binding energy; ionization potential; computational; electronic structure; self-consistent field; DFT; QM MM; gas phase; liquid; solution; physisorption; metallic surface; polymer; charge transfer; Teoretisk kemi och biologi; Theoretical Chemistry and Biology;

    Sammanfattning : Computational quantum chemistry methods have been applied in two particular cases: to provide insight to photoionization induced fragmentation of HgBr2 and HgCl2 molecules, and to study core-electron binding energies and chemical shifts of molecules in liquid, surface adsorbed and polymeric environments in the framework of quantum mechanics/molecular mechanics (QM/MM). In the photodissociation studies the computational work is based on the relativistic Dirac equation as the systems present strong spin-orbit interaction affecting the fragmentation processes. LÄS MER