3QSK

5 Histidine Variant of the anti-RNase A VHH in Complex with RNAse A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.184 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

A combinatorial histidine scanning library approach to engineer highly pH-dependent protein switches.

Murtaugh, M.L.Fanning, S.W.Sharma, T.M.Terry, A.M.Horn, J.R.

(2011) Protein Sci. 20: 1619-1631

  • DOI: 10.1002/pro.696

  • PubMed Abstract: 
  • There is growing interest in the development of protein switches, which are proteins whose function, such as binding a target molecule, can be modulated through environmental triggers. Efforts to engineer highly pH sensitive protein-protein interacti ...

    There is growing interest in the development of protein switches, which are proteins whose function, such as binding a target molecule, can be modulated through environmental triggers. Efforts to engineer highly pH sensitive protein-protein interactions typically rely on the rational introduction of ionizable groups in the protein interface. Such experiments are typically time intensive and often sacrifice the protein's affinity at the permissive pH. The underlying thermodynamics of proton-linkage dictate that the presence of multiple ionizable groups, which undergo a pK(a) change on protein binding, are necessary to result in highly pH-dependent binding. To test this hypothesis, a novel combinatorial histidine library was developed where every possible combination of histidine and wild-type residue is sampled throughout the interface of a model anti-RNase A single domain VHH antibody. Antibodies were coselected for high-affinity binding and pH-sensitivity using an in vitro, dual-function selection strategy. The resulting antibodies retained near wild-type affinity yet became highly sensitive to small decreases in pH, drastically decreasing their binding affinity, due to the incorporation of multiple histidine groups. Several trends were observed, such as histidine "hot-spots," which will help enhance the development of pH switch proteins as well as increase our understanding of the role of ionizable residues in protein interfaces. Overall, the combinatorial approach is rapid, general, and robust and should be capable of producing highly pH-sensitive protein affinity reagents for a number of different applications.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Ribonuclease pancreatic
A
124Bos taurusMutation(s): 0 
Gene Names: RNASE1 (RNS1)
EC: 3.1.27.5
Find proteins for P61823 (Bos taurus)
Go to Gene View: RNASE1
Go to UniProtKB:  P61823
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Engineered 5 Histidine anti-RNase A Camelid VHH Antibody Domain Variant
B
123N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.246 
  • R-Value Work: 0.184 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 40.787α = 90.00
b = 54.680β = 109.24
c = 48.792γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
REFMACrefinement
HKL-2000data collection
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-08-10
    Type: Initial release
  • Version 1.1: 2011-11-30
    Type: Database references