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  • 1
    Publication Date: 2010-09-25
    Description: Gram-negative bacteria, such as Escherichia coli, frequently use tripartite efflux complexes in the resistance-nodulation-cell division (RND) family to expel various toxic compounds from the cell. The efflux system CusCBA is responsible for extruding biocidal Cu(I) and Ag(I) ions. No previous structural information was available for the heavy-metal efflux (HME) subfamily of the RND efflux pumps. Here we describe the crystal structures of the inner-membrane transporter CusA in the absence and presence of bound Cu(I) or Ag(I). These CusA structures provide new structural information about the HME subfamily of RND efflux pumps. The structures suggest that the metal-binding sites, formed by a three-methionine cluster, are located within the cleft region of the periplasmic domain. This cleft is closed in the apo-CusA form but open in the CusA-Cu(I) and CusA-Ag(I) structures, which directly suggests a plausible pathway for ion export. Binding of Cu(I) and Ag(I) triggers significant conformational changes in both the periplasmic and transmembrane domains. The crystal structure indicates that CusA has, in addition to the three-methionine metal-binding site, four methionine pairs-three located in the transmembrane region and one in the periplasmic domain. Genetic analysis and transport assays suggest that CusA is capable of actively picking up metal ions from the cytosol, using these methionine pairs or clusters to bind and export metal ions. These structures suggest a stepwise shuttle mechanism for transport between these sites.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946090/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2946090/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Long, Feng -- Su, Chih-Chia -- Zimmermann, Michael T -- Boyken, Scott E -- Rajashankar, Kanagalaghatta R -- Jernigan, Robert L -- Yu, Edward W -- GM 072014/GM/NIGMS NIH HHS/ -- GM 074027/GM/NIGMS NIH HHS/ -- GM 081680/GM/NIGMS NIH HHS/ -- GM 086431/GM/NIGMS NIH HHS/ -- R01 GM072014/GM/NIGMS NIH HHS/ -- R01 GM074027/GM/NIGMS NIH HHS/ -- R01 GM074027-05/GM/NIGMS NIH HHS/ -- R01 GM086431/GM/NIGMS NIH HHS/ -- R01 GM086431-01A2/GM/NIGMS NIH HHS/ -- RR-15301/RR/NCRR NIH HHS/ -- England -- Nature. 2010 Sep 23;467(7314):484-8. doi: 10.1038/nature09395.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Molecular, Cellular and Developmental Biology Interdepartmental Graduate Program, Iowa State University, Iowa 50011, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20865003" target="_blank"〉PubMed〈/a〉
    Keywords: Apoproteins/chemistry/metabolism ; Binding Sites ; Cell Membrane/metabolism ; Copper/chemistry/*metabolism ; Crystallography, X-Ray ; Cytosol/metabolism ; Escherichia coli/*chemistry ; Escherichia coli Proteins/*chemistry/*metabolism ; Ion Transport ; Membrane Transport Proteins/*chemistry/*metabolism ; Methionine/*metabolism ; Models, Biological ; Models, Molecular ; Periplasm/metabolism ; Protein Structure, Quaternary ; Protein Structure, Tertiary ; Silver/chemistry/*metabolism ; Structure-Activity Relationship
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2016-05-07
    Description: In nature, structural specificity in DNA and proteins is encoded differently: In DNA, specificity arises from modular hydrogen bonds in the core of the double helix, whereas in proteins, specificity arises largely from buried hydrophobic packing complemented by irregular peripheral polar interactions. Here, we describe a general approach for designing a wide range of protein homo-oligomers with specificity determined by modular arrays of central hydrogen-bond networks. We use the approach to design dimers, trimers, and tetramers consisting of two concentric rings of helices, including previously not seen triangular, square, and supercoiled topologies. X-ray crystallography confirms that the structures overall, and the hydrogen-bond networks in particular, are nearly identical to the design models, and the networks confer interaction specificity in vivo. The ability to design extensive hydrogen-bond networks with atomic accuracy enables the programming of protein interaction specificity for a broad range of synthetic biology applications; more generally, our results demonstrate that, even with the tremendous diversity observed in nature, there are fundamentally new modes of interaction to be discovered in proteins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Boyken, Scott E -- Chen, Zibo -- Groves, Benjamin -- Langan, Robert A -- Oberdorfer, Gustav -- Ford, Alex -- Gilmore, Jason M -- Xu, Chunfu -- DiMaio, Frank -- Pereira, Jose Henrique -- Sankaran, Banumathi -- Seelig, Georg -- Zwart, Peter H -- Baker, David -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2016 May 6;352(6286):680-7. doi: 10.1126/science.aad8865.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA. ; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Graduate Program in Biological Physics, Structure, and Design, University of Washington, Seattle, WA 98195, USA. ; Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA. ; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. ; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Department of Computer Science and Engineering, University of Washington, Seattle, WA 98195, USA. ; Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/3, 8010-Graz, Austria. Joint BioEnergy Institute, Emeryville, CA 94608, USA. ; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. ; Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA. Berkeley Center for Structural Biology, Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA. ; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. The Center for Advanced Mathematics for Energy Research Applications, Lawrence Berkeley National Laboratories, 1 Cyclotron Road, Berkeley, CA 94720, USA. ; Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA. dabaker@u.washington.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/27151862" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2019
    Description: 〈p〉The ability of naturally occurring proteins to change conformation in response to environmental changes is critical to biological function. Although there have been advances in the de novo design of stable proteins with a single, deep free-energy minimum, the design of conformational switches remains challenging. We present a general strategy to design pH-responsive protein conformational changes by precisely preorganizing histidine residues in buried hydrogen-bond networks. We design homotrimers and heterodimers that are stable above pH 6.5 but undergo cooperative, large-scale conformational changes when the pH is lowered and electrostatic and steric repulsion builds up as the network histidine residues become protonated. The transition pH and cooperativity can be controlled through the number of histidine-containing networks and the strength of the surrounding hydrophobic interactions. Upon disassembly, the designed proteins disrupt lipid membranes both in vitro and after being endocytosed in mammalian cells. Our results demonstrate that environmentally triggered conformational changes can now be programmed by de novo protein design.〈/p〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2018-03-06
    Description: The computational design of transmembrane proteins with more than one membrane-spanning region remains a major challenge. We report the design of transmembrane monomers, homodimers, trimers, and tetramers with 76 to 215 residue subunits containing two to four membrane-spanning regions and up to 860 total residues that adopt the target oligomerization state in detergent solution. The designed proteins localize to the plasma membrane in bacteria and in mammalian cells, and magnetic tweezer unfolding experiments in the membrane indicate that they are very stable. Crystal structures of the designed dimer and tetramer—a rocket-shaped structure with a wide cytoplasmic base that funnels into eight transmembrane helices—are very close to the design models. Our results pave the way for the design of multispan membrane proteins with new functions.
    Keywords: Biochemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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