Download or read book Structural Characterization of Iron and Copper Active Sites by Resonance Raman Spectroscopy written by Estelle Marie Maes and published by . This book was released on 2000 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biological Applications of Resonance Raman Spectroscopy written by Marzena Barbara Zaczek and published by . This book was released on 2008 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Elucidation of Manganese Iron Vanadium and Copper Active Site Structures written by Bakul C. Dave and published by . This book was released on 1993 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physical Characterization of Diiron dioxygen Complexes and Resonance Raman Studies of Mononuclear Non heme Iron Proteins written by Bridget Anne Brennan and published by . This book was released on 1991 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spectroscopic Studies of Structural and Functional Binuclear Copper Model Complexes of Coupled Binuclear Copper Proteins written by Michael Alan Vance and published by . This book was released on 2007 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book I Resonance Raman Spectra and Electronic Structure of the mu disulfur Bridged Diruthenium Complex H3N 5RuSSRu NH3 5 4 and Related Systems II Spectroscopic and Chemical Characterization of Superoxide written by Soonhee Kang Kim and published by . This book was released on 1982 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spectroscopic and Theoretical Studies of T1 Cu CuA and Cytochrome C written by Xiangjin Xie and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal sites that are known to be involved in biological electron transfer (ET) include Type 1 Copper (T1 Cu), CuA, cytochromes, and the 1-, 2-, 3-, and 4-iron sulfur centers (rubredoxin, ferredoxins, and high potential iron-sulfur proteins (HiPIPs)). These ET sites generally exhibit unusual spectroscopic features reflecting novel geometric and electronic structures that contribute to function. My focuses are on T1 Cu, CuA, cytochrome c proteins utilizing a wide-range of spectroscopies combined with density functional calculations to understand active site electronic structures, the origin of their geometric structures, and possible contributions to function. Five major achievements are: 1) defined the temperature dependent absorption feature of T1 Cu site in nitrite reductase (NIR) and provided insight into the entatic/rack nature of the blue Cu site in plastocyanin; 2) addressed the interesting absorption features of the T1 Cu site in P. pantotrophus pseudoazurin and demonstrated the spectral probes of the weak axial ligation in metalloprotein; 3) resolved a two-state issue in the mixed-valence binuclear CuA centers in cytochrome c oxidases (CcO) and nitrous oxide reductases (N2O) by a combination of density functional calculations and spectroscopy analyses, and evaluated proteins role in CuA sites and their contributions to ET function; 4) determined that the Cu-Cu interaction in CuA keeps the site delocalized even upon loss of a Histidine (NHis) ligand due to protonation, and defined the contribution of [sigma] delocalization to efficient ET; 5) investigated the nature of the Fe-SMet bond in ferricytochrome c. (1) Thermodynamic Equilibrium between Blue and Green Copper Sites and the Role of the Protein in Controlling Function Spectroscopies and density functional theory calculations indicate that there are large temperature-dependent absorption spectral changes present in green nitrite reductases (NiRs) due to a thermodynamic equilibrium between a green and a blue type 1 (T1) copper site. The axial methionine (Met) ligand is unconstrained in the oxidized NiRs, which results in an enthalpically favored ([delta]H [approximately equal to] 4.6 kcal/mol) Met-bound green copper site at low temperatures, and an entropically favored (T[delta]S [approximately equal to] 4.5 kcal/mol, at room temperature) Met-elongated blue copper site at elevated temperatures. In contrast to the NiRs, the classic blue copper sites in plastocyanin and azurin show no temperature-dependent behavior, indicating that a single species is present at all temperatures. For these blue copper proteins, the polypeptide matrix opposes the gain in entropy that would be associated with the loss of the weak axial Met ligand at physiological temperatures by constraining its coordination to copper. The potential energy surfaces of Met binding indicate that it stabilizes the oxidized state more than the reduced state. This provides a mechanism to tune down the reduction potential of blue copper sites by> 200 mV. (2) Variable Temperature Spectroscopic Study on Pseudoazurin: Effects of Protein Constraints on the Blue Cu Site. The T1 copper site of Paracoccus pantotrophus pseudoazurin exhibits significant absorption intensity in both the 450 and 600 nm regions. These are [sigma] and [pi] SCys to Cu2+ charge transfer (CT) transitions. The temperature dependent absorption, EPR, and resonance Raman (rR) vibrations enhanced by these bands indicate that a single species is present at all temperatures. This contrasts the temperature dependent behavior of the T1 center in nitrite reductase, which has a thioether ligand that is unconstrained by the protein. The lack of temperature dependence in the T1 site in pseudoazurin indicates the presence of a protein constraint similar to the blue Cu site in plastocyanin where the thioether ligand is constrained at 2.8 Å. However, plastocyanin exhibits only [pi] CT. This spectral difference between pseudoazurin and plastocyanin reflects a coupled distortion of the site where the axial thioether in pseudoazurin is also constrained, but at a shorter Cu--SMet bond length. This leads to an increase in the Cu2+--SCys bond length, and the site undergoes a partial tetragonal distortion in pseudoazurin. Thus, its ground state wavefunction has both [sigma] and [pi] character in the Cu2+--SCys bond. (3) The Two State Issue in the Mixed-Valence Binuclear CuA Center in Cytochrome c Oxidase and N2O Reductase For the CuA site in the protein, the ground and lowest energy excited-states are [sigma]u* and [pi]u, respectively, denoting the types of Cu-Cu interactions. EPR data on CuA proteins show a low g[vertical line][vertical line] value of 2.19 deriving from spin-orbital coupling between [sigma]u* and [pi]u, which requires an energy gap between [sigma]u* and [pi]u of 3000-4500 cm-1. On the other hand, from paramagnetic NMR studies, it has been observed that the first excited-state is thermally accessible and the energy gap between the ground state and the thermally accessible state is 350 cm-1. This study addressed this apparent discrepancy and evaluated the roles of the two electronic states, [sigma]u* and [pi]u, in electron transfer (ET) of CuA. The potential energy surface calculations show that both NMR and EPR results are consistent within the electronic/geometric structure of CuA. The anti-Curie behavior observed in paramagnetic NMR studies of CuA results from the thermal equilibrium between the [sigma]u* and [pi]u states, which are at very close energies in their respective equilibrium geometries. Alternatively, the EPR g-value analysis involves the [sigma]u* ground state in the geometry with a short dCu-Cu where the [pi]u state is a Frank-Condon excited-state with the energy of 3200 cm-1. The protein environment plays a role in maintaining CuA in the [sigma]u* state as a lowest-energy state with the lowest reorganization energy and high-covalent coupling to the Cys and His ligands for efficient intra- and intermolecular ET with a low-driving force. (4) Perturbations to the Geometric and Electronic Structure of the CuA Site: Factors that Influence Delocalization and their Contributions to Electron Transfer Using a combination of electronic spectroscopies and DFT calculations, the effect of pH perturbation on the geometric and electronic structure of the CuA site has been defined. Descriptions are developed for high pH (pH = 7) and low pH (pH = 4) forms of CuA azurin and its H120A mutant which address the discrepancies concerning the extent of delocalization indicated by multifrequency EPR and ENDOR data. Our resonance Raman and MCD spectra demonstrate that the low pH and H120A mutant forms are essentially identical and are the perturbed forms of the completely delocalized high pH CuA site. However, in going from high pH to low pH, a seven-line hyperfine coupling pattern associated with complete delocalization of the electron (S = 1/2) over two Cu coppers (ICu = 3/2) changes into a four-line pattern reflecting apparent localization. DFT calculations show that the unpaired electron is delocalized in the low pH form and reveal that its four-line hyperfine pattern results from the large EPR spectral effects of 1% 4s orbital contribution of one Cu to the ground-state spin wave function upon protonative loss of its His ligand. The contribution of the Cu-Cu interaction to electron delocalization in this low symmetry protein site is evaluated, and the possible functional significance of the pH-dependent transition in regulating proton-coupled electron transfer in cytochrome c oxidase is discussed. (5) The Fe-Smet Bond in Ferricytochrome c DFT calculations calibrated with experiment data were used to define the nature of the Fe-SMet bond in ferricytochrome c. This is inspired by the studies of NiR.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Doctoral Dissertations written by and published by . This book was released on 2000 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Solid Materials and Heterogeneous Catalysts written by Michel Che and published by John Wiley & Sons. This book was released on 2012-04-16 with total page 1313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two-volume book provides an overview of physical techniques used to characterize the structure of solid materials, on the one hand, and to investigate the reactivity of their surface, on the other. Therefore this book is a must-have for anyone working in fields related to surface reactivity. Among the latter, and because of its most important industrial impact, catalysis has been used as the directing thread of the book. After the preface and a general introduction to physical techniques by M. Che and J.C. Vedrine, two overviews on physical techniques are presented by G. Ertl and Sir J.M. Thomas for investigating model catalysts and porous catalysts, respectively. The book is organized into four parts: Molecular/Local Spectroscopies, Macroscopic Techniques, Characterization of the Fluid Phase (Gas and/ or Liquid), and Advanced Characterization. Each chapter focuses upon the following important themes: overview of the technique, most important parameters to interpret the experimental data, practical details, applications of the technique, particularly during chemical processes, with its advantages and disadvantages, conclusions.

Download or read book Biomedical Index to PHS supported Research written by and published by . This book was released on 1990 with total page 866 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Directory of Graduate Research written by American Chemical Society. Committee on Professional Training and published by . This book was released on 2005 with total page 1932 pages. Available in PDF, EPUB and Kindle. Book excerpt: Faculties, publications and doctoral theses in departments or divisions of chemistry, chemical engineering, biochemistry and pharmaceutical and/or medicinal chemistry at universities in the United States and Canada.

Download or read book Research Awards Index written by and published by . This book was released on 1989 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cumulated Index Medicus written by and published by . This book was released on 2000 with total page 1796 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1987 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1987 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biomedical Index to PHS supported Research pt A Subject access A H written by and published by . This book was released on 1992 with total page 1192 pages. Available in PDF, EPUB and Kindle. Book excerpt: