8VGN

CryoEM structure of CD20 in complex with wild type Rituximab Fab


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 2.50 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


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Literature

Disulfide constrained Fabs overcome target size limitation for high-resolution single-particle cryo-EM.

Kung, J.E.Johnson, M.C.Jao, C.C.Arthur, C.P.Tegunov, D.Rohou, A.Sudhamsu, J.

(2024) bioRxiv 

  • DOI: https://doi.org/10.1101/2024.05.10.593593
  • Primary Citation of Related Structures:  
    8VEG, 8VGE, 8VGF, 8VGG, 8VGH, 8VGI, 8VGJ, 8VGK, 8VGL, 8VGM, 8VGN, 8VGO, 8VGP, 8VGQ

  • PubMed Abstract: 

    High-resolution structures of proteins are critical to understanding molecular mechanisms of biological processes and in the discovery of therapeutic molecules. Cryo-EM has revolutionized structure determination of large proteins and their complexes 1 , but a vast majority of proteins that underlie human diseases are small (< 50 kDa) and usually beyond its reach due to low signal-to-noise images and difficulties in particle alignment 2 . Current strategies to overcome this problem increase the overall size of small protein targets using scaffold proteins that bind to the target, but are limited by inherent flexibility and not being bound to their targets in a rigid manner, resulting in the target being poorly resolved compared to the scaffolds 3-11 . Here we present an iteratively engineered molecular design for transforming Fabs (antibody fragments), into conformationally rigid scaffolds (Rigid-Fabs) that, when bound to small proteins (~20 kDa), can enable high-resolution structure determination using cryo-EM. This design introduces multiple disulfide bonds at strategic locations, generates a well-folded Fab constrained into a rigid conformation and can be applied to Fabs from various species, isotypes and chimeric Fabs. We present examples of the Rigid Fab design enabling high-resolution (2.3-2.5 Å) structures of small proteins, Ang2 (26 kDa) and KRAS (21 kDa) by cryo-EM. The strategies for designing disulfide constrained Rigid Fabs in our work thus establish a general approach to overcome the target size limitation of single particle cryo-EM.


  • Organizational Affiliation

    Department of Structural Biology, Genentech Inc., South San Francisco, CA 94080, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Rituximab Fab heavy chainA,
D [auth H]
229Homo sapiensMutation(s): 0 
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Rituximab Fab light chainB,
F [auth L]
213Homo sapiensMutation(s): 0 
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  • Reference Sequence
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
B-lymphocyte antigen CD20C [auth G],
E [auth I]
278Homo sapiensMutation(s): 0 
Gene Names: MS4A1CD20
Membrane Entity: Yes 
UniProt & NIH Common Fund Data Resources
Find proteins for P11836 (Homo sapiens)
Explore P11836 
Go to UniProtKB:  P11836
PHAROS:  P11836
GTEx:  ENSG00000156738 
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UniProt GroupP11836
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 2.50 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
RECONSTRUCTIONcryoSPARC
MODEL REFINEMENTPHENIX1.21rc1_5049

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2024-11-06
    Type: Initial release