Structural and functional studies of heavy metal ATPases

Research output: Book/anthology/dissertation/reportPh.D. thesisResearch

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  • PhD_thesis

    Accepted manuscript, 49.5 MB, PDF document

  • Oleg Sitsel
Copper and zinc are trace elements that are crucial for the well-being of all cells and are an indispensable part of many proteins. At the same time, the intracellular levels of these metals require careful regulation, as an excess or deficiency may be lethal. P1B-ATPases are key players in Cu+ and Zn2+ homeostasis that belong to the superfamily of P-type ATPases, transmembrane proteins which are present in virtually all lifeforms, with functions ranging from membrane potential generation to muscle relaxation. The goal of this thesis is to improve our understanding of P1B-ATPases by focusing on the bacterial proteins LpCopA and SsZntA, which represent Cu+- and Zn2+-ATPases, respectively. The thesis first compares the recent pioneering P1B-ATPase structure of LpCopA to that of the well-described Ca2+-ATPase SERCA, showing how Cu+-ATPases have managed to adapt the general P-type ATPase topology to handle heavy metal ions. LpCopA is then compared to its two human homologues ATP7A and ATP7B, which cause the severe Menkes and Wilson diseases when malfunctioning. The differences between the three proteins are described and disease-causing mutations in the human proteins are analyzed. The crystal structure of LpCopA in a new conformational state is then presented and studied using a variety of methods, showing that Cu+-ATPases use an ion release pathway unique for the P-type ATPase superfamily. The next section introduces the two pioneering crystal structures of a Zn2+-ATPase, SsZntA. Investigation of SsZntA using a broad range of techniques reveals an array of unique Zn2+-ATPase features relating to ion uptake, binding, discharge and countertransport. These results are then used to comprehensively compare Zn2+-ATPases with their Cu+-transporting counterparts, showing how the two have managed to adapt to transport of distinct ion types while still maintaining all the major features of the P1B-ATPase subclass.
Original languageEnglish
Number of pages236
Commissioning bodyGraduate School of Science and Technology
Publication statusPublished - 28 Aug 2015

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