PDBsum entry 4zuu

Immune system

PDB id: 4zuu

Contents

Protein chains

274 a.a.

99 a.a.

Ligands

CYS-THR-SER-GLU-GLU-MET-ASN-ALA-PHE

Waters ×130

PDB id:

4zuu

Name:

Immune system

Title:

Crystal structure of equine mhc i(eqca-n 00602) In complexed with equine infectious anaemia virus (eiav) derived peptide gag-cf9

Structure:

Classical mhc class i antigen. Chain: a. Fragment: unp residues 22-295. Engineered: yes. Beta-2-microglobulin. Chain: b. Fragment: unp residues 21-119. Engineered: yes. Mutation: yes.

Source:

Equus caballus. Horse. Organism_taxid: 9796. Expressed in: escherichia coli. Expression_system_taxid: 562. Mus musculus. Mouse. Organism_taxid: 10090. Gene: b2m.

Resolution:

2.20Å R-factor: 0.230 R-free: 0.266

Authors:

S.Yao,J.Liu,J.Qi,R.Chen,N.Zhang,Y.Liu,C.Xia

Key ref:

S.Yao et al. (2016). Structural Illumination of Equine MHC Class I Molecules Highlights Unconventional Epitope Presentation Manner That Is Evolved in Equine Leukocyte Antigen Alleles. J Immunol, 196, 1943-1954. PubMed id: 26764037 DOI: 10.4049/jimmunol.1501352

Date:

17-May-15 Release date: 06-Apr-16

Protein chain

Q860N6  (Q860N6_HORSE) -  Classical MHC class I antigen from Equus caballus

Seq: 357 a.a.

Struc: 274 a.a.

Protein chain

P01887  (B2MG_MOUSE) -  Beta-2-microglobulin from Mus musculus

Seq: 119 a.a.

Struc: 99 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.4049/jimmunol.1501352

J Immunol 196:1943-1954 (2016)

PubMed id: 26764037

Structural Illumination of Equine MHC Class I Molecules Highlights Unconventional Epitope Presentation Manner That Is Evolved in Equine Leukocyte Antigen Alleles.

S.Yao, J.Liu, J.Qi, R.Chen, N.Zhang, Y.Liu, J.Wang, Y.Wu, G.F.Gao, C.Xia.

ABSTRACT

MHC class I (MHC I)-restricted virus-specific CTLs are implicated as critical components in the control of this naturally occurring lentivirus and in the protective immune response to the successfully applied attenuated equine infectious anemia virus vaccine in the horse. Nevertheless, the structural basis for how the equine MHC I presents epitope peptides remains unknown. In this study, we investigated the binding of several equine infectious anemia virus-derived epitope peptides by the ability to refold recombinant molecules and by thermal stability, and then by determining the x-ray structure of five peptide-MHC I complexes: equine MHC class I allele (Eqca)-N*00602/Env-RW12, Eqca-N*00602/Gag-GW12, Eqca-N*00602/Rev-QW11, Eqca-N*00602/Gag-CF9, and Eqca-N*00601/Gag-GW12. Although Eqca-N*00601 and Eqca-N*00602 differ by a single amino acid, Eqca-N*00601 exhibited a drastically different peptide presentation when binding a similar CTL epitope, Gag-GW12; the result makes the previously reported function clear to be non-cross-recognition between these two alleles. The structures plus Eqca-N*00602 complexed with a 9-mer peptide are particularly noteworthy in that we illuminated differences in apparent flexibility in the center of the epitope peptides for the complexes with Gag-GW12 as compared with Env-RW12, and a strict selection of epitope peptides with normal length. The featured preferences and unconventional presentations of long peptides by equine MHC I molecules provide structural bases to explain the exceptional anti-lentivirus immunity in the horse. We think that the beneficial reference points could serve as an initial platform for other human or animal lentiviruses.