PDBsum entry 3m19

Immune system

PDB id: 3m19

Contents

Protein chains

237 a.a. *

Waters ×328

* Residue conservation analysis

PDB id:

3m19

Name:

Immune system

Title:

Crystal structure of variable lymphocyte receptor vlra.R5.1

Structure:

Variable lymphocyte receptor a diversity region. Chain: a, b. Fragment: ectodomain. Engineered: yes

Source:

Petromyzon marinus. Marine lamprey. Organism_taxid: 7757. Gene: vlra. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.70Å R-factor: 0.212 R-free: 0.255

Authors:

L.Deng,C.A.Velikovsky,R.A.Mariuzza

Key ref:

L.Deng et al. (2010). A structural basis for antigen recognition by the T cell-like lymphocytes of sea lamprey. Proc Natl Acad Sci U S A, 107, 13408-13413. PubMed id: 20616002

Date:

04-Mar-10 Release date: 30-Jun-10

Protein chains

C7B6Z3  (C7B6Z3_PETMA) -  Variable lymphocyte receptor A diversity region (Fragment) from Petromyzon marinus

Seq: 250 a.a.

Struc: 237 a.a.

Proc Natl Acad Sci U S A 107:13408-13413 (2010)

PubMed id: 20616002

A structural basis for antigen recognition by the T cell-like lymphocytes of sea lamprey.

L.Deng, C.A.Velikovsky, G.Xu, L.M.Iyer, S.Tasumi, M.C.Kerzic, M.F.Flajnik, L.Aravind, Z.Pancer, R.A.Mariuzza.

ABSTRACT

Adaptive immunity in jawless vertebrates is mediated by leucine-rich repeat proteins called "variable lymphocyte receptors" (VLRs). Two types of VLR (A and B) are expressed by mutually exclusive lymphocyte populations in lamprey. VLRB lymphocytes resemble the B cells of jawed vertebrates; VLRA lymphocytes are similar to T cells. We determined the structure of a high-affinity VLRA isolated from lamprey immunized with hen egg white lysozyme (HEL) in unbound and antigen-bound forms. The VLRA-HEL complex demonstrates that certain VLRAs, like gammadelta T-cell receptors (TCRs) but unlike alphabeta TCRs, can recognize antigens directly, without a requirement for processing or antigen-presenting molecules. Thus, these VLRAs feature the nanomolar affinities of antibodies, the direct recognition of unprocessed antigens of both antibodies and gammadelta TCRs, and the exclusive expression on the lymphocyte surface that is unique to alphabeta and gammadelta TCRs.