4PPT

Engineered Dual Specific VHH Antibody in Complex with a Nickel (II) Ion


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis of an engineered dual-specific antibody: conformational diversity leads to a hypervariable loop metal-binding site.

Fanning, S.W.Walter, R.Horn, J.R.

(2014) Protein Eng.Des.Sel. 27: 391-397

  • DOI: 10.1093/protein/gzu033
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • To explore dual-specificity in a small protein interface, we previously generated a 'metal switch' anti-RNase A VHH antibody using a combinatorial histidine library approach. While most metal-binding sites in proteins are found within rigid secondary ...

    To explore dual-specificity in a small protein interface, we previously generated a 'metal switch' anti-RNase A VHH antibody using a combinatorial histidine library approach. While most metal-binding sites in proteins are found within rigid secondary structure, the engineered VHH antibody (VHH(metal)), which contained three new histidine residues, possessed metal-binding residues within the flexible hypervariable loops. Here, crystal structure analysis of the free and bound states of VHH(metal) reveals the structural determinants leading to dual-function. Most notably, CDR1 is observed in two distinct conformations when adopting the metal or RNase A bound states. Furthermore, mutagenesis studies revealed that one of the engineered residues, not located in the metal-binding pocket, contributed indirectly to metal recognition, likely through influencing CDR1 conformation. Despite these changes, VHH(metal) possesses a relatively minor energetic penalty toward binding the original antigen, RNase A (~1 kcal/mol), where the engineered gain-of-function metal-binding residues are observed to possess a mix of favorable and unfavorable contributions towards RNase A recognition. Ultimately, the conformationally distinct metal-switch interface architecture reflects the robust, library-based strategy used to produce VHH(metal). These results also suggest that even small protein interfaces, such as VHH, may be structurally and energetically forgiving in adopting novel function, while maintaining original function.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA Current address: Ben May Department for Cancer Research, University of Chicago, 929 E. 57th St., Chicago, IL 60637, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Engineered single domain VHH antibody
A
121N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

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Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
NI
Query on NI

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Download CCD File 
A
NICKEL (II) ION
Ni
VEQPNABPJHWNSG-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.192 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 53.824α = 90.00
b = 61.926β = 90.00
c = 66.319γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data scaling
PHASERphasing
HKL-2000data reduction
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-09-03
    Type: Initial release
  • Version 1.1: 2014-10-01
    Type: Structure summary
  • Version 1.2: 2014-10-22
    Type: Database references