title: De novo design of a transmembrane Zn²⁺-transporting four-helix bundle.
abstract: The design of functional membrane proteins from first principles represents a grand challenge in chemistry and structural biology. Here, we report the design of a membrane-spanning, four-helical bundle that transports first-row transition metal ions Zn(2+) and Co(2+), but not Ca(2+), across membranes. The conduction path was designed to contain two di-metal binding sites that bind with negative cooperativity. X-ray crystallography and solid-state and solution nuclear magnetic resonance indicate that the overall helical bundle is formed from two tightly interacting pairs of helices, which form individual domains that interact weakly along a more dynamic interface. Vesicle flux experiments show that as Zn(2+) ions diffuse down their concentration gradients, protons are antiported. These experiments illustrate the feasibility of designing membrane proteins with predefined structural and dynamic properties.
authors.affiliation: Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
authors.forename: Nathan H
authors.initials: NH
authors.lastname: Joh
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Tuo
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
authors.forename: Manasi P
authors.initials: MP
authors.lastname: Bhate
authors.affiliation: School of Biological Sciences, National Institute of Science Education and Research, Bhubaneswar, Odisha, India.
authors.forename: Rudresh
authors.initials: R
authors.lastname: Acharya
authors.affiliation: Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
authors.forename: Yibing
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA. william.degrado@ucsf.edu gevorg.grigoryan@dartmouth.edu meihong@mit.edu michael.grabe@ucsf.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Grabe
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. william.degrado@ucsf.edu gevorg.grigoryan@dartmouth.edu meihong@mit.edu michael.grabe@ucsf.edu.
authors.forename: Mei
authors.initials: M
authors.lastname: Hong
authors.affiliation: Department of Computer Science and Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA. william.degrado@ucsf.edu gevorg.grigoryan@dartmouth.edu meihong@mit.edu michael.grabe@ucsf.edu.
authors.forename: Gevorg
authors.initials: G
authors.lastname: Grigoryan
authors.affiliation: Department of Pharmaceutical Chemistry, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA. william.degrado@ucsf.edu gevorg.grigoryan@dartmouth.edu meihong@mit.edu michael.grabe@ucsf.edu.
authors.forename: William F
authors.initials: WF
authors.lastname: DeGrado
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D017136:Ion Transport; D008051:Lipid Bilayers; D008565:Membrane Proteins / Q000737:chemistry*; D008823:Micelles; D056004:Molecular Dynamics Simulation; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D015032:Zinc / Q000737:chemistry*
chemical_list: D002352:Carrier Proteins; D008051:Lipid Bilayers; D008565:Membrane Proteins; D008823:Micelles; C017800:zinc-binding protein; D015032:Zinc