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PDBsum entry 1qqe
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Protein transport
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PDB id
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1qqe
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Crystal structure of the vesicular transport protein sec17: implications for snap function in snare complex disassembly.
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Authors
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L.M.Rice,
A.T.Brunger.
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Ref.
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Mol Cell, 1999,
4,
85-95.
[DOI no: ]
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PubMed id
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Abstract
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SNAP proteins play an essential role in membrane trafficking in eukaryotic
cells. They activate and recycle SNARE proteins by serving as adaptors between
SNAREs and the cytosolic chaperone NSF. We have determined the crystal structure
of Sec17, the yeast homolog of alpha-SNAP, to 2.9 A resolution. Sec17 is
composed of an N-terminal twisted sheet of alpha-helical hairpins and a
C-terminal alpha-helical bundle. The N-terminal sheet has local similarity to
the tetratricopeptide repeats from protein phosphatase 5 but has a different
overall twist. Sec17 also shares structural features with HEAT and clathrin
heavy chain repeats. Possible models of SNAP:SNARE binding suggest that SNAPs
may function as lever arms, transmitting forces generated by conformational
changes in NSF/Sec18 to drive disassembly of SNARE complexes.
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Figure 1.
Figure 1. Experimental Electron Density Map after Density
ModificationDensity-modified experimental electron density for
α helices α3 and α4 and the connecting loop contoured at 1.4
σ. The final, refined model is shown using a ball-and-stick
representation. The α helices, loop, and most side chains are
clearly visible in the initial map. The buried residues Gly-57,
Phe-60, Ala-83, and Phe-87, which are conserved in the
representative SNAP sequences (Figure 3A), are depicted in red.
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Figure 2.
Figure 2. Overall Structure of Sec17Two ribbon drawings of
Sec17 related by a 180° rotation around the long axis of the
protein. The nine N-terminal α helices form a twisted sheet
that gives rise to two faces and two ridges. The five C-terminal
α helices form a more globular bundle, which is
asymmetrically disposed with respect to the N-terminal sheet,
creating a significant cleft on one face of the molecule.
Residues colored red and yellow correspond, respectively, to
inhibitory and noninhibitory peptides from an earlier study
([15]).
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The above figures are
reprinted
by permission from Cell Press:
Mol Cell
(1999,
4,
85-95)
copyright 1999.
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