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Figure 1.
Figure 1: Cbl domain structure and sequence comparisons. a,
Ribbon diagram of unliganded Cbl-N. The N-terminal 4H domain is
coloured yellow, the EF-hand domain green, and the SH2 domain
blue. Secondary-structure elements are labelled  A–
D
in the 4H domain and by established conventions for the
EF-hand and SH2 domains. The bound Ca^2+ ion is indicated by a
red sphere. Arginine 294 is universally conserved in SH2 domains
and participates in phosphotyrosine coordination. b, Diagram of
c-Cbl domain structure. The Cbl-N region and adjacent RING
finger domain are conserved in all Cbl homologues. The
C-terminal region, which contains proline-rich segments and
tyrosine phosphorylation sites, is more variable and is
completely absent in D-Cbl. A putative leucine zipper has been
found near the C terminus of Cbl. c, Aligned sequences of the
Cbl-N portion of human c-Cbl, human Cbl-b, Drosophila D-Cbl, and
Sli-1. Residues that are identical in at least three of the
sequences are shaded yellow. Secondary-structure elements are
shown above the sequence and are coloured as in a and b. Black
squares indicate residues that coordinate calcium. Red circles
mark residues that interact with the bound ZAP-70 peptide. d,
Structure-based sequence alignment of Cbl and Lck^23 SH2
domains. Seventy structurally equivalent residues are shaded
yellow; -carbons
of these seventy residues superimpose with an r.m.s.d. of 1.47
Å. The secondary-structure elements that are present in
Lck and other SH2 domains, but not in the Cbl SH2 domain, are
indicated by open boxes. e, Superposition of the Cbl SH2 domain
(blue) with the Lck SH2 domain (yellow). The structural elements
that are absent in the Cbl domain are red.
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