PDBsum entry 1ac6

Receptor

PDB id: 1ac6

Contents

Protein chains

110 a.a. *

Waters ×116

* Residue conservation analysis

PDB id:

1ac6

Name:

Receptor

Title:

Crystal structure of a variable domain mutant of a t-cell receptor alpha chain

Structure:

T-cell receptor alpha. Chain: a, b. Fragment: variable domain. Mutation: yes

Source:

Mus musculus. House mouse. Organism_taxid: 10090

Resolution:

2.30Å R-factor: 0.161 R-free: 0.279

Authors:

H.-M.Li,R.A.Mariuzza

Key ref:

H.Li et al. (1997). Dual conformations of a T cell receptor V alpha homodimer: implications for variability in V alpha V beta domain association. J Mol Biol, 269, 385-394. PubMed id: 9199407 DOI: 10.1006/jmbi.1997.1047

Date:

13-Feb-97 Release date: 25-Feb-98

Protein chains

Q5R1F5  (Q5R1F5_MOUSE) -  TRAV6D-7 (Fragment) from Mus musculus

Seq: 112 a.a.

Struc: 110 a.a.

DOI no: 10.1006/jmbi.1997.1047

J Mol Biol 269:385-394 (1997)

PubMed id: 9199407

Dual conformations of a T cell receptor V alpha homodimer: implications for variability in V alpha V beta domain association.

H.Li, M.I.Lebedeva, E.S.Ward, R.A.Mariuzza.

ABSTRACT

The crystal structure of a mutant T cell receptor (TCR) V alpha domain containing a grafted third complementarity-determining region (CDR3) from a different V alpha was determined at 2.3 A resolution by molecular replacement using the wild-type V alpha structure as a search model. Like the wild-type V alpha domain, the mutant crystallized as a homodimer very similar to TCR V alpha V beta and antibody V(L)V(H) heterodimers, with the CDR loops disposed to form part of the antigen-binding site. However, the relative orientation of the two chains in the mutant V alpha homodimer differs from that in the wild-type by a rotation of 14 degrees such that the buried surface area in the dimer interface of the mutant is 140 A2 less than in the wild-type. While the residues forming the interface are essentially the same in the two structures, there are only four pairs of interface hydrogen bonds in the case of the mutant compared with eight for the wild-type. These results suggest that multiple relative orientations of the V alpha and V beta domains of TCRs may be possible, providing a significant contribution to TCR combining site diversity.

Selected figure(s)

Figure 2.
Figure 2. The 2 F[o]−F[c] electron density maps for 1934.4 Vα[mut] CDR loops. A, CDR1; B, CDR2 and C, CDR3 of monomer 1. D, CDR3 of monomer 2. Maps are contoured at 1 σ for CDR1 and CDR2 and at 0.6 σ for CDR3. Hydrogen bonds are dotted pink lines. Carbon, nitrogen and oxygen atoms are colored yellow, blue and red, respectively.

Figure 3.
Figure 3. Stereoview of VαVα dimers showing hydrogen bonds and water molecules in the domain interfaces of mutant (A) and wild-type (B) 1934.4 Vα structures. Monomers 1 and 2 are colored blue and yellow, respectively. Hydrogen bonds are dotted pink lines and water molecules are red spheres. Nitrogen and oxygen atoms are colored blue and red, respectively.

The above figures are reprinted by permission from Elsevier: J Mol Biol (1997, 269, 385-394) copyright 1997.

Figures were selected by an automated process.