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Figure 3.
Figure 3. N-Terminal Domain Interactions in the TIM Receptors
(A and B) Ribbon diagrams of the two domains in the
asymmetric unit of the mTIM-2 (A) and mTIM-1 (B) crystals. Side
view of the dimer is displayed for mTIM-2, whereas a view along
the quasi-2-fold axis (2) is shown for mTIM-1. Molecules
presented in Figure 1 have the same coloring scheme, and the
neighboring molecules are in yellow. Side chains of residues
contributing to the dimer interfaces are included and some
central residues are labeled. Acetate ligand found in the mTIM-2
structure is black, water molecules are red spheres, and
hydrogen bonds are pink dashed cylinders. Asn residues to which
glycans link in mTIM-2 are green. Arrows represent the
hypothetical interaction of O-linked glycans from the C-terminal
mucin domain with residues at the β strand A, BC, and FG loops
of the interacting mTIM-1 domains (see also Figure S3).
(C)
Self-association of the N-terminal IgV domains in solution.
SDS-PAGE under reducing conditions of mTIM-1, mTIM-2, and mTIM-4
domains untreated (−) or treated with the indicated BS^3
crosslinker concentration (mM). Treated ICAM-1 protein (IC1-2D)
known to dimerize at high concentration and a soluble fragment
of CD46 are also included. Size and migration of the molecular
weight marker is indicated. Crosslinked dimers are labeled with
an asterisk. No dimerization of the mTIM-4 IgV domain is seen
here or in the protein crystals (not shown).
(D) Structural
alignment with residues at the dimer interface in yellow and
those at the center of the interacting molecules in blue. β
strands are represented by lines.
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