6PYC image
Entry Detail
PDB ID:
6PYC
Keywords:
Title:
Structure of kappa-on-heavy (KoH) antibody Fab bound to the cardiac hormone marinobufagenin
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2019-07-29
Release Date:
2019-12-25
Method Details:
Experimental Method:
Resolution:
3.60 Å
R-Value Free:
0.28
R-Value Work:
0.23
R-Value Observed:
0.23
Space Group:
I 4 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:anti-kappa antibody Fab heavy chain
Chain IDs:C (auth: A)
Chain Length:223
Number of Molecules:1
Biological Source:Mus musculus
Polymer Type:polypeptide(L)
Description:anti-kappa antibody Fab light chain
Chain IDs:D (auth: B)
Chain Length:214
Number of Molecules:1
Biological Source:Mus musculus
Polymer Type:polypeptide(L)
Description:KoH body Fab heavy chain
Chain IDs:A (auth: H)
Chain Length:214
Number of Molecules:1
Biological Source:Mus musculus
Polymer Type:polypeptide(L)
Description:KoH body Fab light chain
Chain IDs:B (auth: L)
Chain Length:215
Number of Molecules:1
Biological Source:Mus musculus
Primary Citation
Kappa-on-Heavy (KoH) bodies are a distinct class of fully-human antibody-like therapeutic agents with antigen-binding properties.
Proc.Natl.Acad.Sci.USA 117 292 299 (2020)
PMID: 31879340 DOI: 10.1073/pnas.1901734117

Abstact

We describe a Kappa-on-Heavy (KoH) mouse that produces a class of highly diverse, fully human, antibody-like agents. This mouse was made by replacing the germline variable sequences of both the Ig heavy-chain (IgH) and Ig kappa (IgK) loci with the human IgK germline variable sequences, producing antibody-like molecules with an antigen binding site made up of 2 kappa variable domains. These molecules, named KoH bodies, structurally mimic naturally existing Bence-Jones light-chain dimers in their variable domains and remain wild-type in their antibody constant domains. Unlike artificially diversified, nonimmunoglobulin alternative scaffolds (e.g., DARPins), KoH bodies consist of a configuration of normal Ig scaffolds that undergo natural diversification in B cells. Monoclonal KoH bodies have properties similar to those of conventional antibodies but exhibit an enhanced ability to bind small molecules such as the endogenous cardiotonic steroid marinobufagenin (MBG) and nicotine. A comparison of crystal structures of MBG bound to a KoH Fab versus a conventional Fab showed that the KoH body has a much deeper binding pocket, allowing MBG to be held 4 Å further down into the combining site between the 2 variable domains.

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