Search for dissertations about: "NATURVETENSKAP Kemi Teoretisk kemi Kvantkemi"
Showing result 16 - 20 of 47 swedish dissertations containing the words NATURVETENSKAP Kemi Teoretisk kemi Kvantkemi.
-
16. Charged Polymers: From DNA to Polyampholytes
Abstract : Three main themes are outlined in this thesis: Polyelectrolytes/DNA : In a living cell, DNA molecules have a compact conformation in order to fit in, while in a test tube they will take on an expanded cylindrical shape, due to the negative phosphate groups along the DNA molecule. With the help of computer simulations it has been shown that like-charged monomers of a poly- electrolyte can attract each other if the counterions are taken into account. READ MORE
-
17. Quantum Chemical Interpretation of Protein Crystal Structure
Abstract : An initial model in the crystallographic structure determination process, usually contains many errors. To produce an accurate model, one must carry out several cycles of crystallographic refinement. READ MORE
-
18. Theoretical Studies of Cytochrome P450
Abstract : The cytochromes P450 are a large enzyme family that is found in all living organisms and takes part in both endogenous and exogenous metabolism. They are primarily mono-oxygenases and perform a wide range of reactions. READ MORE
-
19. Theoretical studies of porphyrin proteins
Abstract : Different aspects of porphyrin proteins have been studied with theoretical methods. For example, we have studied: - The importance of hydrogen bonds for the discrimination between carbon monoxide and molecular oxygen by myoglobin, the oxygen carrier in muscles, modelling the active site both in vacuum and in the protein matrix - The inner-sphere reorganisation energy during electron transfer for cytochromes compared to other electron-transfer proteins, such as blue copper proteins and Fe-S clusters - The role of porphyrin distortions in the reaction mechanism of ferrochelatase, the enzyme that inserts an iron ion into protoporphyrin IX to make haem - The interaction between different metal sites in ferrochelatase In these studies we have used density functional theory, classical force field methods, and a combination of quantum chemistry and molecular mechanics. READ MORE
-
20. Studies of molecular systems with multiconfigurational methods
Abstract : Research in theoretical chemistry is aimed at finding computational algorithms that produce as accurate results as possible, for as large molecules as possible, with a minimum of computational effort and to apply these methods to molecular systems of chemical interest. The most accurate theoretical methods, often referred to as ab initio methods, are derived from the fundamental laws of physics and they do not rely on any empirical information. READ MORE
