PDBsum entry 4ztp

Immune system

PDB id: 4ztp

Contents

Protein chains

216 a.a.

223 a.a.

Waters ×624

PDB id:

4ztp

Name:

Immune system

Title:

Fab structure of rabbit monoclonal antibody r53 targeting an epitope in HIV-1 gp120 c4 region

Structure:

Light chain of fab fragment of rabbit monoclonal antibody r53. Chain: l. Engineered: yes. Heavy chain of fab fragment of rabbit monoclonal antibody r53. Chain: h. Engineered: yes

Source:

Oryctolagus cuniculus. Organism_taxid: 9986. Expressed in: homo sapiens. Expression_system_taxid: 9606. Expression_system_taxid: 9606

Resolution:

1.63Å R-factor: 0.196 R-free: 0.228

Authors:

R.Pan,X.-P.Kong

Key ref:

R.Pan et al. (2015). Structural analysis of a novel rabbit monoclonal antibody R53 targeting an epitope in HIV-1 gp120 C4 region critical for receptor and co-receptor binding. Emerg Microbes Infect, 4, e44. PubMed id: 26251831 DOI: 10.1038/emi.2015.44

Date:

14-May-15 Release date: 19-Aug-15

Protein chain

No UniProt id for this chain

Struc: 216 a.a.

Protein chain

No UniProt id for this chain

Struc: 223 a.a.

DOI no: 10.1038/emi.2015.44

Emerg Microbes Infect 4:e44 (2015)

PubMed id: 26251831

Structural analysis of a novel rabbit monoclonal antibody R53 targeting an epitope in HIV-1 gp120 C4 region critical for receptor and co-receptor binding.

R.Pan, Y.Chen, M.Vaine, G.Hu, S.Wang, S.Lu, X.P.Kong.

ABSTRACT

The fourth conserved region (C4) in the HIV-1 envelope glycoprotein (Env) gp120 is a structural element that is important for its function, as it binds to both the receptor CD4 and the co-receptor CCR5/CXCR4. It has long been known that this region is highly immunogenic and that it harbors B-cell as well as T-cell epitopes. It is the target of a number of antibodies in animal studies, which are called CD4-blockers. However, the mechanism by which the virus shields itself from such antibody responses is not known. Here, we determined the crystal structure of R53 in complex with its epitope peptide using a novel anti-C4 rabbit monoclonal antibody R53. Our data show that although the epitope of R53 covers a highly conserved sequence (433)AMYAPPI(439), it is not available in the gp120 trimer and in the CD4-bound conformation. Our results suggest a masking mechanism to explain how HIV-1 protects this critical region from the human immune system.