Sökning: "Amino Acid Radicals"

Visar resultat 1 - 5 av 18 avhandlingar innehållade orden Amino Acid Radicals.

1. 1. Exploring amino-acid radicals and quinone redox chemistry in model proteins

   Författare :Kristina Westerlund; Cecilia Tommos; Astrid Gräslund; Sara Linse; Stockholms universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; amino-acid radicals; quinone redox chemistry; model proteins; protein redesign; electrochemistry; Biochemistry; Biokemi; biokemi; Biochemistry;

   Sammanfattning : Amino-acid radical enzymes have been studied extensively for 30 years but the experimental barriers to determine the thermodynamic properties of their key radical cofactors are so challenging that only a handful of reports exist in the literature. This is a major drawback when trying to understand the long-range radical transfer and/or catalytic mechanisms of this important family of enzymes. LÄS MER

3. 2. Using de novo design proteins to explore tyrosine radicals and cation-π interactions

   Författare :Bruce W. Berry; Cecilia Tommos; Anders Hofer; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tyrosine; radicals; cation-pi interactions; de novo designed proteins; biochemistry; biophysics; Biochemistry; biokemi;

   Sammanfattning : Redox cofactors and amino-acid free radicals play important roles in biology. Although many of the same cofactors and amino acids that form these radicals are found across a broad range of biological systems, identical cofactors can have different reduction potentials. The local environment plays a role in defining these redox potentials. LÄS MER

4. 3. Mechanistic Studies on Proton-Coupled Electron Transfer from Tyrosine and Tryptophan Derivatives

   Författare :Astrid Nilsen-Moe; Leif Hammarström; Pia Ädelroth; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Proton-Coupled Electron Transfer; PCET; Tyrosine; Tryptophan; Amino Acid Radicals; Transient Absorption; Chemistry with specialization in Physical Chemistry; Kemi med inriktning mot fysikalisk kemi;

   Sammanfattning : Proton-coupled electron transfer (PCET) from tyrosine (Y) and tryptophan (W) is vital to many redox reactions in Nature where PCET between several Ys, or Ws, or between a mix of Ys and Ws can be used to transfer electrons, or protons, or both over large distances of several Å. Studying the PCET reaction mechanisms of Y and W is important for fundamental knowledge, and can help researchers that wish to mimic redox reactions in Nature. LÄS MER

5. 4. Thiyl radicals, reaction kinetics and redox chemistry

   Författare :Rong Zhao; KTH; []
   Nyckelord :;

   Sammanfattning : In focusing on the free radical chemistry of thiyl radicals,two importantclasses are dealt with, namely, the amino acidalkylthiyl and the acylthiyl radicals, where pulse radiolysisand steady state γ-radiolysis are applied.Amino acid thiyl radicals (RS•), are important in manybiological systems,as intermediates in the repair reactions ofthiols towards targeted carbon-centeredradicals and ascatalytic centers in many enzymatic reactions. LÄS MER

7. 5. Quantum chemical calculations of electron paramagnetic resonance of biological radicals

   Författare :Maria Engström; Shashi Karna; Linköpings universitet; []
   Nyckelord :;

   Sammanfattning : The aim of this thesis was to use state-of-the-art quantum chemical calculations of electron paramagnetic resonance (EPR) with applications to radicals in biomolecular systems. Special emphasis has been devoted to investigations of structure-to-property relations of amino acid radicals and spin labels in proteins. LÄS MER