3RDQ

Crystal structure of R7-2 streptavidin complexed with desthiobiotin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.190 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.163 

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This is version 1.3 of the entry. See complete history


Literature

Evolved streptavidin mutants reveal key role of loop residue in high-affinity binding.

Magalhaes, M.L.Czekster, C.M.Guan, R.Malashkevich, V.N.Almo, S.C.Levy, M.

(2011) Protein Sci 20: 1145-1154

  • DOI: 10.1002/pro.642
  • Primary Citation of Related Structures:  
    3RDM, 3RDO, 3RDQ, 3RDS, 3RDU, 3RDX, 3RE5, 3RE6

  • PubMed Abstract: 
  • We have performed a detailed analysis of streptavidin variants with altered specificity towards desthiobiotin. In addition to changes in key residues which widen the ligand binding pocket and accommodate the more structurally flexible desthiobiotin, the data revealed the role of a key, non-active site mutation at the base of the flexible loop (S52G) which slows dissociation of this ligand by approximately sevenfold ...

    We have performed a detailed analysis of streptavidin variants with altered specificity towards desthiobiotin. In addition to changes in key residues which widen the ligand binding pocket and accommodate the more structurally flexible desthiobiotin, the data revealed the role of a key, non-active site mutation at the base of the flexible loop (S52G) which slows dissociation of this ligand by approximately sevenfold. Our data suggest that this mutation results in the loss of a stabilizing contact which keeps this loop open and accessible in the absence of ligand. When this mutation was introduced into the wild-type protein, destabilization of the opened loop conferred a ∼10-fold decrease in both the on-rate and off-rate for the ligand biotin-4-fluoroscein. A similar effect was observed when this mutation was added to a monomeric form of this protein. Our results provide key insight into the role of the streptavidin flexible loop in ligand binding and maintaining high affinity interactions.


    Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
StreptavidinA153Streptomyces avidiniiMutation(s): 6 
UniProt
Find proteins for P22629 (Streptomyces avidinii)
Explore P22629 
Go to UniProtKB:  P22629
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP22629
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
DTB
Query on DTB

Download Ideal Coordinates CCD File 
B [auth A]6-(5-METHYL-2-OXO-IMIDAZOLIDIN-4-YL)-HEXANOIC ACID
C10 H18 N2 O3
AUTOLBMXDDTRRT-JGVFFNPUSA-N
 Ligand Interaction
GOL
Query on GOL

Download Ideal Coordinates CCD File 
E [auth A],
F [auth A]
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
NI
Query on NI

Download Ideal Coordinates CCD File 
C [auth A]NICKEL (II) ION
Ni
VEQPNABPJHWNSG-UHFFFAOYSA-N
 Ligand Interaction
NA
Query on NA

Download Ideal Coordinates CCD File 
D [auth A]SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Binding Affinity Annotations 
IDSourceBinding Affinity
DTB Binding MOAD:  3RDQ Kd: 0.49 (nM) from 1 assay(s)
PDBBind:  3RDQ Kd: 0.49 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.190 
  • R-Value Work: 0.161 
  • R-Value Observed: 0.163 
  • Space Group: I 41 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 57.275α = 90
b = 57.275β = 90
c = 183.742γ = 90
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PHASERphasing
REFMACrefinement
PDB_EXTRACTdata extraction
CBASSdata collection
HKL-2000data reduction

Structure Validation

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Ligand Structure Quality Assessment 



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-07-06
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2016-04-06
    Changes: Non-polymer description
  • Version 1.3: 2018-01-24
    Changes: Structure summary