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Figure 1.
(a) Structure-based sequence alignment of the cytoplasmic
domains of the Cl^- channels ClC-1 and ClC-0 and the Cl^-
transporter ClC-5. Identical residues are highlighted in green,
similar residues in yellow, residues involved in ATP binding in
violet and the recognition sequence for ubiquitin ligase (ClC-5)
in red. Secondary structure and numbering (ClC-5) are indicated
above and below the sequences, respectively. The R-helix with
the Cl^--coordinating tyrosine residue (#) preceding the domains
is included in the alignment. The linker sequence between the
two CBS domains and the C terminus in ClC-0 and ClC-1 have been
omitted (XXX). The first residue of the crystallized construct
is highlighted (^*). h, H. sapiens; t, T. marmorata; hClC-5,
GenBank 116734718; tClC-0, GenBank X56758; hClC-1, GenBank
M97820. (b) Ribbon representation of the ClC-0 domain. The two
CBS subdomains are colored in green and blue, respectively;
residues of the ubiquitin ligase recognition sequence are
colored in red. The bound ATP molecule is shown as CPK model.
(c) Relative arrangement of CBS domains in ClC-5 (yellow) and
ClC-0 (red). For the ClC-0 arrangement, the two CBS subdomains
of ClC-5 were superimposed on their respective counterparts in
ClC-0. (d) Dimeric organization of two cytoplasmic domains of
ClC-5 (colored as in a), as observed in the crystal structure.
The ATP molecule is shown as CPK model. Two-fold axis of
symmetry is indicated. All structure images were prepared with
DINO (http://www.dino3d.org).
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