Biophysical Studies of Function and Stability in Adenylosuccinate Lyase

ORAL

Abstract

Adenylosuccinate Lyase (ADSL) is a homotetrameric protein with four active sites that accommodate two reactions in the de novo purine biosynthesis pathway. ~It catalyzes the conversion of SAICAR to AICAR and AMPS to AMP. ~Point mutations in the gene encoding the protein ADSL lead to ADSL deficiency, a disorder characterized by serious neurological and physiological symptoms. ~Two leading hypotheses regarding the pathogenesis are ``Loss of Function'' or ``Gain in Toxic Function.'' ~These hypotheses can be related to the reduction of either the enzyme kinetics or the stability of the tetramer structure. ~Enzymatic studies can be used to provide a quantitative measure of the extent to which the enzyme acts on its designated substrates, SAICAR and AMPS. ~Recent kinetic studies have measured activity only on the substrates independently. ~Here we present characterization of enzyme kinetics for the biophysically interesting and physiologically relevant case where two substrates exhibit competitive binding to the enzyme, for both wild type and disease causing mutants of ADSL. Preliminary data suggest equivalent specific activities may be necessary to suppress severe phenotypes from expressing. Additionally, we will present results on the role of mutations on the thermodynamic stability of the enzyme. We will discuss thermodynamic analysis that gives a direct quantitative measure of the propensity of formation of folded and unfolded states of the protein, which influence the functionality of the protein and may also influence aggregation.

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Authors

  • Stephen Ray

    University of Denver

  • Norm Buchanan

    Brigham Young University, Stanford University, University of Central Florida, NCAR/High Altitude Observatory, Arizona Vitro-retinal consultants, University of Michigan, Arizona State University, University of Denver, Arizona State University Dept of Physics, Arizona State University Dept of Chemistry and Biochemistry, LASP, University of Colorado Boulder, Center for Atmospheric and Space Science, Utah State University, Dixie State College, Utah, USU Materials Physics Group, UVU Physics Department, Box Elder Innovations, Space Telescope Science Institute, Northern Kentucky University, Retired, Utah Valley University, Univ. of California, Los Angelos, Colorado State University, St. Petersburg Electro-technical University, Universidad Nacional Aut\'onoma de M\'exico, New Mexico State University, University of New Mexico, University of Wurtzberg, Theoretical Division, Los Alamos National Laboratory, National High Magnetic Field Laboratory, LANL, UCLA, Max-planck-Institut f\"{u}r Astronomie, W. M. Keck Observatory, University of Arizona, Nuclear Physics Group, Brigham Young University, GLOBALFOUNDRIES, IBM Systems and Technology Group, IBM Research Division, T.J. Watson Research Center, Sandia National Laboratory, NMSU, Military University of Technology, Warsaw, Poland, James Franck Institute and Department of Physics, University of Chicago, Department of Atmospheric Sciences, University of Washington, JISAO, University of Washington, New Mexico Institute of Mining and Technology, NorthWest Research Associates, University of Alaska, Fairbanks, Utah State University, New Mexico Tech, University of Cambridge, Los Alamos National Laboratory, RAPTOR Science, Institute of Space and Astronomical Science, Japanese Aerospace Exploration Agency, Weber State University, Department of Physics, New Mexico State University, BYU Physics, Physics Department, University of Arizona, ABQMR, University of Colorado at Boulder, SNL and CINT, Los Alamos National Lab, Center for Quantum Information and Control, University of Arizona, Center for Quantum Information and Control, University of New Mexico, University of Calgary, Colorado School of Mines

  • Norm Buchanan

    Brigham Young University, Stanford University, University of Central Florida, NCAR/High Altitude Observatory, Arizona Vitro-retinal consultants, University of Michigan, Arizona State University, University of Denver, Arizona State University Dept of Physics, Arizona State University Dept of Chemistry and Biochemistry, LASP, University of Colorado Boulder, Center for Atmospheric and Space Science, Utah State University, Dixie State College, Utah, USU Materials Physics Group, UVU Physics Department, Box Elder Innovations, Space Telescope Science Institute, Northern Kentucky University, Retired, Utah Valley University, Univ. of California, Los Angelos, Colorado State University, St. Petersburg Electro-technical University, Universidad Nacional Aut\'onoma de M\'exico, New Mexico State University, University of New Mexico, University of Wurtzberg, Theoretical Division, Los Alamos National Laboratory, National High Magnetic Field Laboratory, LANL, UCLA, Max-planck-Institut f\"{u}r Astronomie, W. M. Keck Observatory, University of Arizona, Nuclear Physics Group, Brigham Young University, GLOBALFOUNDRIES, IBM Systems and Technology Group, IBM Research Division, T.J. Watson Research Center, Sandia National Laboratory, NMSU, Military University of Technology, Warsaw, Poland, James Franck Institute and Department of Physics, University of Chicago, Department of Atmospheric Sciences, University of Washington, JISAO, University of Washington, New Mexico Institute of Mining and Technology, NorthWest Research Associates, University of Alaska, Fairbanks, Utah State University, New Mexico Tech, University of Cambridge, Los Alamos National Laboratory, RAPTOR Science, Institute of Space and Astronomical Science, Japanese Aerospace Exploration Agency, Weber State University, Department of Physics, New Mexico State University, BYU Physics, Physics Department, University of Arizona, ABQMR, University of Colorado at Boulder, SNL and CINT, Los Alamos National Lab, Center for Quantum Information and Control, University of Arizona, Center for Quantum Information and Control, University of New Mexico, University of Calgary, Colorado School of Mines

  • Norm Buchanan

    Brigham Young University, Stanford University, University of Central Florida, NCAR/High Altitude Observatory, Arizona Vitro-retinal consultants, University of Michigan, Arizona State University, University of Denver, Arizona State University Dept of Physics, Arizona State University Dept of Chemistry and Biochemistry, LASP, University of Colorado Boulder, Center for Atmospheric and Space Science, Utah State University, Dixie State College, Utah, USU Materials Physics Group, UVU Physics Department, Box Elder Innovations, Space Telescope Science Institute, Northern Kentucky University, Retired, Utah Valley University, Univ. of California, Los Angelos, Colorado State University, St. Petersburg Electro-technical University, Universidad Nacional Aut\'onoma de M\'exico, New Mexico State University, University of New Mexico, University of Wurtzberg, Theoretical Division, Los Alamos National Laboratory, National High Magnetic Field Laboratory, LANL, UCLA, Max-planck-Institut f\"{u}r Astronomie, W. M. Keck Observatory, University of Arizona, Nuclear Physics Group, Brigham Young University, GLOBALFOUNDRIES, IBM Systems and Technology Group, IBM Research Division, T.J. Watson Research Center, Sandia National Laboratory, NMSU, Military University of Technology, Warsaw, Poland, James Franck Institute and Department of Physics, University of Chicago, Department of Atmospheric Sciences, University of Washington, JISAO, University of Washington, New Mexico Institute of Mining and Technology, NorthWest Research Associates, University of Alaska, Fairbanks, Utah State University, New Mexico Tech, University of Cambridge, Los Alamos National Laboratory, RAPTOR Science, Institute of Space and Astronomical Science, Japanese Aerospace Exploration Agency, Weber State University, Department of Physics, New Mexico State University, BYU Physics, Physics Department, University of Arizona, ABQMR, University of Colorado at Boulder, SNL and CINT, Los Alamos National Lab, Center for Quantum Information and Control, University of Arizona, Center for Quantum Information and Control, University of New Mexico, University of Calgary, Colorado School of Mines

  • Norm Buchanan

    Brigham Young University, Stanford University, University of Central Florida, NCAR/High Altitude Observatory, Arizona Vitro-retinal consultants, University of Michigan, Arizona State University, University of Denver, Arizona State University Dept of Physics, Arizona State University Dept of Chemistry and Biochemistry, LASP, University of Colorado Boulder, Center for Atmospheric and Space Science, Utah State University, Dixie State College, Utah, USU Materials Physics Group, UVU Physics Department, Box Elder Innovations, Space Telescope Science Institute, Northern Kentucky University, Retired, Utah Valley University, Univ. of California, Los Angelos, Colorado State University, St. Petersburg Electro-technical University, Universidad Nacional Aut\'onoma de M\'exico, New Mexico State University, University of New Mexico, University of Wurtzberg, Theoretical Division, Los Alamos National Laboratory, National High Magnetic Field Laboratory, LANL, UCLA, Max-planck-Institut f\"{u}r Astronomie, W. M. Keck Observatory, University of Arizona, Nuclear Physics Group, Brigham Young University, GLOBALFOUNDRIES, IBM Systems and Technology Group, IBM Research Division, T.J. Watson Research Center, Sandia National Laboratory, NMSU, Military University of Technology, Warsaw, Poland, James Franck Institute and Department of Physics, University of Chicago, Department of Atmospheric Sciences, University of Washington, JISAO, University of Washington, New Mexico Institute of Mining and Technology, NorthWest Research Associates, University of Alaska, Fairbanks, Utah State University, New Mexico Tech, University of Cambridge, Los Alamos National Laboratory, RAPTOR Science, Institute of Space and Astronomical Science, Japanese Aerospace Exploration Agency, Weber State University, Department of Physics, New Mexico State University, BYU Physics, Physics Department, University of Arizona, ABQMR, University of Colorado at Boulder, SNL and CINT, Los Alamos National Lab, Center for Quantum Information and Control, University of Arizona, Center for Quantum Information and Control, University of New Mexico, University of Calgary, Colorado School of Mines

  • Norm Buchanan

    Brigham Young University, Stanford University, University of Central Florida, NCAR/High Altitude Observatory, Arizona Vitro-retinal consultants, University of Michigan, Arizona State University, University of Denver, Arizona State University Dept of Physics, Arizona State University Dept of Chemistry and Biochemistry, LASP, University of Colorado Boulder, Center for Atmospheric and Space Science, Utah State University, Dixie State College, Utah, USU Materials Physics Group, UVU Physics Department, Box Elder Innovations, Space Telescope Science Institute, Northern Kentucky University, Retired, Utah Valley University, Univ. of California, Los Angelos, Colorado State University, St. Petersburg Electro-technical University, Universidad Nacional Aut\'onoma de M\'exico, New Mexico State University, University of New Mexico, University of Wurtzberg, Theoretical Division, Los Alamos National Laboratory, National High Magnetic Field Laboratory, LANL, UCLA, Max-planck-Institut f\"{u}r Astronomie, W. M. Keck Observatory, University of Arizona, Nuclear Physics Group, Brigham Young University, GLOBALFOUNDRIES, IBM Systems and Technology Group, IBM Research Division, T.J. Watson Research Center, Sandia National Laboratory, NMSU, Military University of Technology, Warsaw, Poland, James Franck Institute and Department of Physics, University of Chicago, Department of Atmospheric Sciences, University of Washington, JISAO, University of Washington, New Mexico Institute of Mining and Technology, NorthWest Research Associates, University of Alaska, Fairbanks, Utah State University, New Mexico Tech, University of Cambridge, Los Alamos National Laboratory, RAPTOR Science, Institute of Space and Astronomical Science, Japanese Aerospace Exploration Agency, Weber State University, Department of Physics, New Mexico State University, BYU Physics, Physics Department, University of Arizona, ABQMR, University of Colorado at Boulder, SNL and CINT, Los Alamos National Lab, Center for Quantum Information and Control, University of Arizona, Center for Quantum Information and Control, University of New Mexico, University of Calgary, Colorado School of Mines