Crystal structure and mechanistic basis of a functional homolog of the antigen transporter tap

Anne Nöll, Christoph Thomas, Valentimãng cầu Herbring, Tina Zollmann, Katja Barth, Ahmad Reza Mehdipour, Thomas M. Tomasiak, Stengười Brüchert, Benesh Joseph, Rupert Abele, Vincent Oliéric, Meitian Wang, Kay Diederichs, View ORCID ProfileGerhard Hummer, Robert M. Stroud, Klaas M. Pos, and Robert Tampé


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vinaanh.com January 24, 2017 114 (4) E438-E447; first published January 9, 2017; https://doi.org/10.1073/vinaanh.com.1620009114
aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
bInstitute of Physical & Theoretical Chemistry, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;


Xem thêm: Bộ Phim Đồng Tình Luyến Ái Nam Có Gì Khác Biệt Trong Phim Và Trong Đời?

aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
bInstitute of Physical và Theoretical Chemistry, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;
aInstitute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany;

Contributed by Robert M. Stroud, December 7, 2016 (sent for Đánh Giá October 24, 2016; reviewed by Douglas C. Rees và Daniel M. Rosenbaum)




Xem thêm: Thăm Ngôi Làng Cổ Hallstatt Áo, Kinh Nghiệm Du Lịch Hallstatt Áo

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Fig. 7.

Conformational dynamics of TmrAB và the catalytic transport cycle. (A) Relative movement of the NBDs during the transport cycle, analyzed by superimposing the NBDs of TmrB (pale cyan), TM287, and of one Sav1866 protomer; P-loop, Walker B, và D-loop of the superimposed NBDs are shown in transparent colors. Structural elements of the NBD moving relative khổng lồ the superimposed domains are depicted in opaque colors. (B) Structural side-by-side comparison of TmrAB with alternating conformations displayed by TM288/287 and Sav1866. (Top) Schematic outline of the NBDs with the positions of the C-terminal helices highlighted by trắng rectangles. The relative sầu positions of the two C-terminal helices are marked by a wheat and cyan dot. The red arrows indicate the movement of the two C-terminal helices. The red C stands for the C terminus. (Bottom) View onto lớn the TMDs from the periplasmic side showing the closed state of the periplasmic gate in TmrAB & TM288/287, và the open state in Sav1866. The Cα atoms of two glycines are shown as red spheres (G291 in TmrA and G276 in TmrB, và corresponding positions in TM288/287 và Sav1866). (C) Model of substrate transport by TmrAB and the role of the zipper helices. TmrAB (subunits shown as schematic outlines) is able lớn transport a diverse range of substrates (depicted as encircled letter “S”), both soluble and membrane-associated compounds. An arginine cluster in TmrB at the ryên ổn of the lateral gate mediates association with headgroups of lipidic substrates. The inward-facing state with juxtaposed NBDs is stabilized by interactions between the C-terminal zipper helices. ATPhường. and substrate binding induce a conformational transition khổng lồ an occluded state, in which the NBDs interact intimately, but the periplasmic gate is still closed. For this transition, the zipper helices must dissolve their interaction and switch their position. The central cavity (shown in dark blue) functions as the cargo compartment that mediates substrate transport from the cytoplasmic khổng lồ the periplasmic side of the membrane. ATP hydrolysis leads lớn periplasmic gate opening, allowing the substrate khổng lồ leave sầu the cavity. Release of phosphate restores the inward-facing state of TmrAB.


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