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Ghezai T. Musie

Research Group

Ghezai T. Musie

  • Ph.D., Inorganic Chemistry: 1997, Texas A&M University

Research Interests

  • Bioinorganic Chemistry: Development of structural and functional mimics of metalloenzymes with bimetallic active sites such as Super Oxide Dismutase and Xylose/Glucose Isomerases
  • Carbon Dioxide Fixation: Synthesis of novel dinuclear metal complexes as catalysts for carbon dioxide reduction
  • Ligand Design and Coordination: Chemistry of unusual geometry and oxidation states of transition metal complexes
  • Carbohydrates form the most abundant group of natural products and are found in all classes of living organisms. As well as serving the direct link between the sun's energy and the metabolic energy that sustains life, carbohydrates also participates in other biological functions. Our research interests lie in the area of coordination chemistry, bioinorganic chemistry and catalysis, focuses on exploiting the reactivity, selectivity and specificity of metalloenzymes to develop biocatalysts. We are particularly interested in cobalt(II) and manganease(II) bimetallic centers of metalloproteins, such as xylose and glucose isomerases. Using synthetic models to study metalloenzymes involved in carbohydrate metabolism is largely unexplored. Xylose/Glucose isomerase, XGI, is an example of such a metalloenzyme. Depicted in below is a synthetic model that closely resembles to the active site of the XGI.
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 Crystal structures of XGI from different bacterial sources and mutants indicate that the active site is composed of a Mn2+/Mn2+, Mn2+/Co2+ or a Co2+/Co2+ bimetallic center. Recently, the crystal structure of the D-glucose bound active site has been reported. While the metal centers are believed to be involved in substrate binding and catalyzing the isomerization of D-xylose/D-xylulose and D-glucose/D-fructose, neither the mode of substrate binding nor the mechanistic role of the metallic active site is understood.
  • Another area of our research focuses in developing metal complexes as catalysts in carbon dioxide fixation.It has been shown that metal complexes, especially of copper(II) complexes and some late second row transition metal ions, are active in chemical reduction of carbon dioxide to formic acid and methanol. Our research has demonstrated that it is possible to design and synthesize copper(II) complexes that are reactive toward the reduction of carbon dioxide. Shown on the side is the crystal structure of one of the copper complex synthesized in our group.

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  • Zinc is essential for several biological processes. Apart from enzymes with one zinc binding site, such as carbonic anhydrase and carboxypeptidase A, enzymes containing more than one zinc ions at the active site are also of interest. Furthermore, the discovery of structural polyzinc(II) nucleic acid polymerases and transcription factors has renewed the interest in zinc coordination chemistry. The most important and distinguishing feature in the coordination chemistry of these polyzinc enzymes is that the metal centers are bridged to each other through OH- and/or H2O as well as the carboxylate groups from amino acid side chains. The reported Zn---Zn internuclear distances range from 3.0 to 3.5 Å. As below, several coordination modes of carboxylate groups to the zinc centers have been manifested. Our group is interested in synthesizing and understanding of coordination chemistry of carboxylate rich novel ligands to different transition metal ions.


Musie Research Group

Musie Research Group


Musie Group Members

Front row from left to right: Rebecca Joy, Manindra Bera, Fabia Palhares
Back row: Dr. Ghezai Musie, Jake Hernandez, Ashley Curtiss


 

Selected Publications
  1. Ashley B. S. Curtiss; Manindranath Bera; Ghezai T. Musie; Douglas R. Powell, Synthesis and characterization of mono- and hexanuclear Zinc µ6-sulfato complexes of a new symmetric dinucleating Ligand. Dalton. Trans, 2008, . In press
  2. Manindranath Bera; Ghezai T. Musie; Douglas R. Powell Zinc(II) mediated cyclization and complexation of an unsymmetrical dicarboxyamine ligand: Synthesis, spectral and crystal structures characterizations. Inorg. Chem. Comm, 2008, 11(3), 293-299.
  3. Xiaobao Li, Manindranath Bera, Ghezai T. Musie; Douglas R. Powell, Copper(II) promoted imidazolidine ring formation and complexation: A unique reaction course. Inorg. Chim. Acta, 2008, 361, 1965-1972.
  4. Ashley B. S. Curtiss; Ghezai T. Musie; Douglas R. Powell, Bis(tetramethylammonium) tetrachloridozincate(II), phase VI. Acta. Cryst. Sec. E, 2008, E64(1), m183-185.
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