8FYM

Crystal structure of Fab235 in complex with MPER peptide

Summary for 8FYM

• Entry DOI: 10.2210/pdb8fym/pdb
• Related: 8FWF
• Descriptor: Fab235, L chain, Fab235, H chain, ALA-SER-LEU-TRP-ASN-TRP-PHE-ASN-ILE-THR-ASN-TRP-LEU-TRP-TYR-ILE-LYS-LYS-LYS, ... (7 entities in total)
• Functional Keywords: mper, membrane proximal external region, vaccucine, fab, immune system
• Biological source: Mus musculus (mouse); More
• Total number of polymer chains: 12
• Total formula weight: 205276.32

Authors

Tan, K.,Kim, M.,Reinherz, E.L. (deposition date: 2023-01-26, release date: 2023-10-11, Last modification date: 2024-11-06)

Primary citation

Tan, K.,Chen, J.,Kaku, Y.,Wang, Y.,Donius, L.,Khan, R.A.,Li, X.,Richter, H.,Seaman, M.S.,Walz, T.,Hwang, W.,Reinherz, E.L.,Kim, M.
Inadequate structural constraint on Fab approach rather than paratope elicitation limits HIV-1 MPER vaccine utility.
Nat Commun, 14:7218-7218, 2023

PubMed Abstract: Broadly neutralizing antibodies (bnAbs) against HIV-1 target conserved envelope (Env) epitopes to block viral replication. Here, using structural analyses, we provide evidence to explain why a vaccine targeting the membrane-proximal external region (MPER) of HIV-1 elicits antibodies with human bnAb-like paratopes paradoxically unable to bind HIV-1. Unlike in natural infection, vaccination with MPER/liposomes lacks a necessary structure-based constraint to select for antibodies with an adequate approach angle. Consequently, the resulting Abs cannot physically access the MPER crawlspace on the virion surface. By studying naturally arising Abs, we further reveal that flexibility of the human IgG3 hinge mitigates the epitope inaccessibility and additionally facilitates Env spike protein crosslinking. Our results suggest that generation of IgG3 subtype class-switched B cells is a strategy for anti-MPER bnAb induction. Moreover, the findings illustrate the need to incorporate topological features of the target epitope in immunogen design.

PubMed: 37940661
DOI: 10.1038/s41467-023-42097-6

Experimental method

X-RAY DIFFRACTION (2.45 Å)