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PDBsum entry 1z47
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Ligand binding protein
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PDB id
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1z47
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References listed in PDB file
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Key reference
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Title
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Structure of the atpase subunit cysa of the putative sulfate atp-Binding cassette (abc) transporter from alicyclobacillus acidocaldarius.
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Authors
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F.Scheffel,
U.Demmer,
E.Warkentin,
A.Hülsmann,
E.Schneider,
U.Ermler.
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Ref.
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FEBS Lett, 2005,
579,
2953-2958.
[DOI no: ]
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PubMed id
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Abstract
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CysA, the ATPase subunit of a putative sulfate ATP-binding cassette transport
system of the gram-positive thermoacidophilic bacterium Alicyclobacillus
acidocaldarius, was structurally characterized at a resolution of 2.0 Angstroms
in the absence of nucleotides. In line with previous findings on ABC-ATPases the
structures of the two monomers (called CysA-1 and CysA-2) in the asymmetric unit
differ substantially in the arrangement of their individual (sub)domains. CysA-2
was found as a physiological dimer composed of two crystallographically related
monomers that are arranged in an open state. Interestingly, while the regulatory
domain of CysA-2 packs against its opposing domain that of CysA-1 undergoes a
conformational change and, in the dimer, would interfere with the opposing
monomer thereby preventing solute translocation. Whether this conformational
state is used for regulatory purposes will be discussed.
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Figure 1.
Fig. 1. Structure of CysA: (a) Ribbon diagram of the CysA
monomer. The catalytic subdomain of the nucleotide-binding
domain is shown in purple, the helical subdomain in red, the
linker region in yellow and the regulatory domain in blue
(distal β-sandwich) and royal blue (proximal β-sandwich). The
location of conserved sequence motifs is indicated by capital
letters: ‘Walker’ sites (A, B), D-loop, Q-loop, ABC
signature (LSQ), and H motif. (b) Stereo representation of the
CysA-2 dimer found in an open state. The monomers were shown in
blue and red. For comparison CysA-2 was superimposed with the
MalK[eco](open) structure at the front side (red) and with the
MalK[eco](close) structure at the back side (green). In
addition, the regulatory domains of the CysA-1 monomers are
shown in yellow after superimposing with the catalytic domain.
Fig. 1 and Fig. 2 have the same orientation and were generated
using BOBSCRIPT [32].
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Figure 2.
Fig. 2. Structural variability of the regulatory domains
of CysA-1 (light-blue), CysA-2 (blue), MalK[tli] (yellow) and
GlcV (pink). The regulatory domains undergo different
conformational changes relative to the catalytic domain;
however, the rotation axis and the direction of translation are
conserved. The rotation axis passes perpendicular through helix
L2 and the translation occurs parallel to the rotation axis.
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The above figures are
reprinted
by permission from the Federation of European Biochemical Societies:
FEBS Lett
(2005,
579,
2953-2958)
copyright 2005.
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