The Structure of the Metal Transporter Tp34 and its Affinity for Divalent Metal Ions

ORAL

Abstract

Tp34 is periplasmic membrane protein of the nonculitvatable spirochete \textit{Treponema pallidum}, the pathogen of syphillis. It was proposed that Tp34 is a divalent metal transporter, but the identity of the preferred metal ion(s) was unclear. In this study we investigated the ability of divalent metal ions to induce rTp34 dimerization using hydrodynamic techniques and determine the crystal structure of metal bound forms. Using analytical ultracentrifugation sedimentation velocity experiments, we determined that cobalt is superior to nickel at inducing the dimerization of rTp34. rTp34 was crystallized and selected crystals were incubated at a pH 7.5 with CuSO$_{4}$ and NiSO$_{4}$. Diffraction experiments were conducted and the processed electron density maps showed that copper was bound to the major metal binding site as well as to three additional minor binding sites. By contrast nickel was only bound to the major metal binding site in one monomer and to three additional minor sites. These results along with previous findings support evidence of Tp34 being involved with metal transport and/or iron utilization.

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Authors

  • Gregory Knutsen

    University of Dallas

  • Edward Fry

    Institute for Astronomy, ETH, National Optical Astronomy Observatory, Department of Physics, ETH, Texas A&M University, LANL, American Physical Society, Society of Physics Students National Office, Texas Tech University, University of Texas, Universite d'Orleans, Steward Observatory, University of Arizona, Texas A\&M University-Commerce, Texas A\&M University, Institute for Quantum Electronics, ETH Zurich, Department of Engineering and Applied Science, Harvard University, Rice University, University of Houston, Bucknell University, Department of Physics, Texas A\&M University, Air Force Research Laboratory, Department of Physics, Texas A\&M University, College Station, TX 77843, Department of Physics and MIC, Texas A\&M University, University of Texas at Arlington, Changwon National University, University of North Texas, Southwestern University, The Pennsylvania State University, University of Dallas, UT Southwestern Medical Center, Naval Air Systems Command, Institute for Quantum Studies and Department of Physics, Texas A\&M University, College Station, TX 77843, The University of Texas at Arlington, TCU, ELTE, National Institute of Chemistry, Ljubljana, Slovenia, Texas Christian University, Fort Worth, TX, Dept. of Physics, Texas A\&M University-Commerce, Univ. of North Texas, Los Alamos National Laboratory, Oswego State University of New York, Lee College, University of Texas at San Antonio, UTSA-Professor, UNT, Sam Houston State University, Sewanee: The University of the South, Director of Education for NSF, Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Sackler School of Chemistry, Tel-Aviv University, Rice University, Department of Physics and Astronomy, Houston, TX 77005, Center for Nonlinear Dynamics, University of Texas at Austin

  • Edward Fry

    Institute for Astronomy, ETH, National Optical Astronomy Observatory, Department of Physics, ETH, Texas A&M University, LANL, American Physical Society, Society of Physics Students National Office, Texas Tech University, University of Texas, Universite d'Orleans, Steward Observatory, University of Arizona, Texas A\&M University-Commerce, Texas A\&M University, Institute for Quantum Electronics, ETH Zurich, Department of Engineering and Applied Science, Harvard University, Rice University, University of Houston, Bucknell University, Department of Physics, Texas A\&M University, Air Force Research Laboratory, Department of Physics, Texas A\&M University, College Station, TX 77843, Department of Physics and MIC, Texas A\&M University, University of Texas at Arlington, Changwon National University, University of North Texas, Southwestern University, The Pennsylvania State University, University of Dallas, UT Southwestern Medical Center, Naval Air Systems Command, Institute for Quantum Studies and Department of Physics, Texas A\&M University, College Station, TX 77843, The University of Texas at Arlington, TCU, ELTE, National Institute of Chemistry, Ljubljana, Slovenia, Texas Christian University, Fort Worth, TX, Dept. of Physics, Texas A\&M University-Commerce, Univ. of North Texas, Los Alamos National Laboratory, Oswego State University of New York, Lee College, University of Texas at San Antonio, UTSA-Professor, UNT, Sam Houston State University, Sewanee: The University of the South, Director of Education for NSF, Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Sackler School of Chemistry, Tel-Aviv University, Rice University, Department of Physics and Astronomy, Houston, TX 77005, Center for Nonlinear Dynamics, University of Texas at Austin

  • Edward Fry

    Institute for Astronomy, ETH, National Optical Astronomy Observatory, Department of Physics, ETH, Texas A&M University, LANL, American Physical Society, Society of Physics Students National Office, Texas Tech University, University of Texas, Universite d'Orleans, Steward Observatory, University of Arizona, Texas A\&M University-Commerce, Texas A\&M University, Institute for Quantum Electronics, ETH Zurich, Department of Engineering and Applied Science, Harvard University, Rice University, University of Houston, Bucknell University, Department of Physics, Texas A\&M University, Air Force Research Laboratory, Department of Physics, Texas A\&M University, College Station, TX 77843, Department of Physics and MIC, Texas A\&M University, University of Texas at Arlington, Changwon National University, University of North Texas, Southwestern University, The Pennsylvania State University, University of Dallas, UT Southwestern Medical Center, Naval Air Systems Command, Institute for Quantum Studies and Department of Physics, Texas A\&M University, College Station, TX 77843, The University of Texas at Arlington, TCU, ELTE, National Institute of Chemistry, Ljubljana, Slovenia, Texas Christian University, Fort Worth, TX, Dept. of Physics, Texas A\&M University-Commerce, Univ. of North Texas, Los Alamos National Laboratory, Oswego State University of New York, Lee College, University of Texas at San Antonio, UTSA-Professor, UNT, Sam Houston State University, Sewanee: The University of the South, Director of Education for NSF, Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Sackler School of Chemistry, Tel-Aviv University, Rice University, Department of Physics and Astronomy, Houston, TX 77005, Center for Nonlinear Dynamics, University of Texas at Austin

  • Edward Fry

    Institute for Astronomy, ETH, National Optical Astronomy Observatory, Department of Physics, ETH, Texas A&M University, LANL, American Physical Society, Society of Physics Students National Office, Texas Tech University, University of Texas, Universite d'Orleans, Steward Observatory, University of Arizona, Texas A\&M University-Commerce, Texas A\&M University, Institute for Quantum Electronics, ETH Zurich, Department of Engineering and Applied Science, Harvard University, Rice University, University of Houston, Bucknell University, Department of Physics, Texas A\&M University, Air Force Research Laboratory, Department of Physics, Texas A\&M University, College Station, TX 77843, Department of Physics and MIC, Texas A\&M University, University of Texas at Arlington, Changwon National University, University of North Texas, Southwestern University, The Pennsylvania State University, University of Dallas, UT Southwestern Medical Center, Naval Air Systems Command, Institute for Quantum Studies and Department of Physics, Texas A\&M University, College Station, TX 77843, The University of Texas at Arlington, TCU, ELTE, National Institute of Chemistry, Ljubljana, Slovenia, Texas Christian University, Fort Worth, TX, Dept. of Physics, Texas A\&M University-Commerce, Univ. of North Texas, Los Alamos National Laboratory, Oswego State University of New York, Lee College, University of Texas at San Antonio, UTSA-Professor, UNT, Sam Houston State University, Sewanee: The University of the South, Director of Education for NSF, Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Sackler School of Chemistry, Tel-Aviv University, Rice University, Department of Physics and Astronomy, Houston, TX 77005, Center for Nonlinear Dynamics, University of Texas at Austin

  • Edward Fry

    Institute for Astronomy, ETH, National Optical Astronomy Observatory, Department of Physics, ETH, Texas A&M University, LANL, American Physical Society, Society of Physics Students National Office, Texas Tech University, University of Texas, Universite d'Orleans, Steward Observatory, University of Arizona, Texas A\&M University-Commerce, Texas A\&M University, Institute for Quantum Electronics, ETH Zurich, Department of Engineering and Applied Science, Harvard University, Rice University, University of Houston, Bucknell University, Department of Physics, Texas A\&M University, Air Force Research Laboratory, Department of Physics, Texas A\&M University, College Station, TX 77843, Department of Physics and MIC, Texas A\&M University, University of Texas at Arlington, Changwon National University, University of North Texas, Southwestern University, The Pennsylvania State University, University of Dallas, UT Southwestern Medical Center, Naval Air Systems Command, Institute for Quantum Studies and Department of Physics, Texas A\&M University, College Station, TX 77843, The University of Texas at Arlington, TCU, ELTE, National Institute of Chemistry, Ljubljana, Slovenia, Texas Christian University, Fort Worth, TX, Dept. of Physics, Texas A\&M University-Commerce, Univ. of North Texas, Los Alamos National Laboratory, Oswego State University of New York, Lee College, University of Texas at San Antonio, UTSA-Professor, UNT, Sam Houston State University, Sewanee: The University of the South, Director of Education for NSF, Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Sackler School of Chemistry, Tel-Aviv University, Rice University, Department of Physics and Astronomy, Houston, TX 77005, Center for Nonlinear Dynamics, University of Texas at Austin