PDBsum entry 6lx3

Immune system

PDB id: 6lx3

Contents

Protein chains

215 a.a.

206 a.a.

209 a.a.

223 a.a.

128 a.a.

509 a.a.

PDB id:

6lx3

Name:

Immune system

Title:

Cryo-em structure of human secretory immunoglobulin a

Structure:

Interleukin-2,immunoglobulin heavy constant alpha 1. Chain: a, b, c, d. Synonym: il-2,t-cell growth factor,tcgf,ig alpha-1 chain c region,ig alpha-1 chain c region bur,ig alpha-1 chain c region tro. Engineered: yes. Immunoglobulin j chain. Chain: j. Synonym: joining chain of multimeric iga and igm. Engineered: yes.

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: il2, igha1. Expressed in: homo sapiens. Expression_system_taxid: 9606. Gene: jchain, igcj, igj. Gene: pigr. Expression_system_taxid: 9606

Authors:

Y.Wang,G.Wang,Y.Li,J.Xiao

Key ref:

Y.Wang et al. (2020). Structural insights into secretory immunoglobulin A and its interaction with a pneumococcal adhesin. Cell Res, 30, 602-609. PubMed id: 32398862 DOI: 10.1038/s41422-020-0336-3

Date:

10-Feb-20 Release date: 27-May-20

Protein chain

P01876  (IGHA1_HUMAN) -  Immunoglobulin heavy constant alpha 1 from Homo sapiens

Seq: 398 a.a.

Struc: 215 a.a.*

Protein chain

P60568  (IL2_HUMAN) -  Interleukin-2 from Homo sapiens

Seq: 153 a.a.

Struc: 215 a.a.*

Protein chain

P01876  (IGHA1_HUMAN) -  Immunoglobulin heavy constant alpha 1 from Homo sapiens

Seq: 398 a.a.

Struc: 206 a.a.*

Protein chain

P60568  (IL2_HUMAN) -  Interleukin-2 from Homo sapiens

Seq: 153 a.a.

Struc: 206 a.a.*

Protein chain

P01876  (IGHA1_HUMAN) -  Immunoglobulin heavy constant alpha 1 from Homo sapiens

Seq: 398 a.a.

Struc: 209 a.a.*

Protein chain

P60568  (IL2_HUMAN) -  Interleukin-2 from Homo sapiens

Seq: 153 a.a.

Struc: 209 a.a.*

Protein chain

P01876  (IGHA1_HUMAN) -  Immunoglobulin heavy constant alpha 1 from Homo sapiens

Seq: 398 a.a.

Struc: 223 a.a.*

Protein chain

P60568  (IL2_HUMAN) -  Interleukin-2 from Homo sapiens

Seq: 153 a.a.

Struc: 223 a.a.*

Protein chain

P01591  (IGJ_HUMAN) -  Immunoglobulin J chain from Homo sapiens

Seq: 159 a.a.

Struc: 128 a.a.

Protein chain

P01833  (PIGR_HUMAN) -  Polymeric immunoglobulin receptor from Homo sapiens

Seq: 764 a.a.

Struc: 509 a.a.

* PDB and UniProt seqs differ at 610 residue positions (black crosses)

DOI no: 10.1038/s41422-020-0336-3

Cell Res 30:602-609 (2020)

PubMed id: 32398862

Structural insights into secretory immunoglobulin A and its interaction with a pneumococcal adhesin.

Y.Wang, G.Wang, Y.Li, Q.Zhu, H.Shen, N.Gao, J.Xiao.

ABSTRACT

Secretory Immunoglobulin A (SIgA) is the most abundant antibody at the mucosal surface. It possesses two additional subunits besides IgA: the joining chain (J-chain) and secretory component (SC). SC is the ectodomain of the polymeric immunoglobulin receptor (pIgR), which functions to transport IgA to the mucosa. How the J-chain and pIgR/SC facilitate the assembly and secretion of SIgA remains incompletely understood. Furthermore, during the infection of Streptococcus pneumoniae, the pneumococcal adhesin SpsA hijacks pIgR/SC and SIgA to gain entry to human cells and evade host defense. How SpsA targets pIgR/SC and SIgA also remains elusive. Here we report a cryo-electron microscopy structure of the Fc region of IgA1 (Fcα) in complex with the J-chain and SC (Fcα-J-SC), which reveals the organization principle of SIgA. We also present a structure of Fcα-J-SC complexed with SpsA, which uncovers the specific interactions between SpsA and human pIgR/SC. These results advance the molecular understanding of SIgA and shed light on S. pneumoniae pathogenesis.