PDBsum entry 1dow

Cell adhesion

PDB id: 1dow

Contents

Protein chains

205 a.a. *

32 a.a. *

Waters ×252

* Residue conservation analysis

References listed in PDB file

Key reference

Title

Structure of the dimerization and beta-Catenin-Binding region of alpha-Catenin.

Authors

S.Pokutta, W.I.Weis.

Ref.

Mol Cell, 2000, 5, 533-543. [DOI no: 10.1016/S1097-2765(00)80447-5]

PubMed id

10882138

Abstract

In adherens junctions, alpha-catenin links the cadherin-beta-catenin complex to the actin-based cytoskeleton. alpha-catenin is a homodimer in solution, but forms a 1:1 heterodimer with beta-catenin. The crystal structure of the alpha-catenin dimerization domain, residues 82-279, shows that alpha-catenin dimerizes through formation of a four-helix bundle in which two antiparallel helices are contributed by each protomer. A slightly larger fragment, comprising residues 57-264, binds to beta-catenin. A chimera consisting of the alpha-catenin-binding region of beta-catenin linked to the amino terminus of alpha-catenin 57-264 behaves as a monomer in solution, as expected, since beta-catenin binding disrupts the alpha-catenin dimer. The crystal structure of this chimera reveals the interaction between alpha- and beta-catenin, and provides a basis for understanding adherens junction assembly.

Figure 1.
Figure 1. Structure of α-cat 82–279(A) Topology diagram of the α-cat 82–279 fold. Helices are shown as cylinders and are numbered consecutively; residue numbers at the beginning and the end of the helices are indicated. The region colored in red represents the dimerization interface.(B) Ribbon diagram of α-cat 82–279 protomer structure. Two different views related by a 180° rotation about the horizontal axis are shown. Proline residues in helices 3 and 4 are shown in red. This figure, and Figure 1 and Figure 5, were made with MOLSCRIPT ( [26]).(C) Ribbon diagram of the α-cat 82–279 dimer.

Figure 4.
Figure 4. Interaction of α- and β-Catenin in βα-cat(A) Superdex 75 gel filtration chromatography of α-cat 57–264 and βα-cat. Peak fractions were analyzed by SDS-PAGE and Coomassie blue staining. The estimated molecular weight for the two peaks is indicated.(B) Ribbon diagram of the chimera βα-cat. The color scheme is the same as in the schematic of the model (Figure 3). Residues 82–261, corresponding to the α-cat 82–279 protomer structure, are in yellow; residues 57–81 of α-catenin are in blue; the β-catenin sequence is in red. The flexible glycine linker between β- and α-catenin, which is not visible in the structure, is shown as a dashed green line; the N and C termini of the α-catenin and the β-catenin fragment are indicated.(C) Contacts formed by tyrosine 142. View of tyrosine 142 in the βα-cat structure. The color scheme is the same as for the βα-cat structure. Amino acids interacting with tyrosine 142 are shown in ball and stick representation. Carbon, nitrogen, and oxygen atoms are shown as gray, blue, and red spheres, respectively. α and β indicate that these amino acids belong to α-catenin and β-catenin, respectively. Nonpolar van der Waals contacts are indicated by thin lines; hydrogen bonds are shown as thin, dashed lines.

The above figures are reprinted by permission from Cell Press: Mol Cell (2000, 5, 533-543) copyright 2000.