1CNU | pdb_00001cnu

PHOSPHORYLATED ACTOPHORIN FROM ACANTAMOEBA POLYPHAGA

• PDB DOI: https://doi.org/10.2210/pdb1CNU/pdb

• Classification: CONTRACTILE
• Organism(s): Acanthamoeba polyphaga
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 1999-05-24 Released: 1999-06-01 
• Deposition Author(s): Blanchoin, L., Robinson, R.C., Choe, S., Pollard, T.D.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.25 Å
• R-Value Free: 
  0.304 (Depositor) 
• R-Value Work: 
  0.204 (Depositor) 

Starting Model: other

Literature

Interaction of actin monomers with Acanthamoeba actophorin (ADF/cofilin) and profilin.

Blanchoin, L., Pollard, T.D.

(1998) J Biological Chem 273: 25106-25111

• PubMed: 9737968 
• DOI: https://doi.org/10.1074/jbc.273.39.25106
• Primary Citation Related Structures: 
  1CNU


• PubMed Abstract: 
  

  Acanthamoeba actophorin is a member of ADF/cofilin family that binds both actin monomers and filaments. We used fluorescence anisotropy to study the interaction of actin monomers with recombinant actophorin labeled with rhodamine on a cysteine substituted for Serine-88. Labeled actophorin retains its affinity for actin and ability to reduce the low shear viscosity of actin filaments. At physiological ionic strength, actophorin binds Mg-ADP-actin monomers (Kd = 0.1 microM) 40 times stronger than Mg-ATP-actin monomers. When bound to actin monomers, actophorin has no effect on elongation at either end of actin filaments by Mg-ATP-actin and slightly increases the rate of elongation at both ends by Mg-ADP-actin. Thus actophorin does not sequester actin monomers. Sedimentation equilibrium ultracentrifugation shows that actophorin and profilin compete for binding actin monomers. Actophorin and profilin have opposite effects on the rate of exchange of nucleotide bound to actin monomers. Despite the high affinity of actophorin for ADP-actin, physiological concentrations of profilin overcome the inhibition of ADP exchange by actophorin. Profilin rapidly recycles ADP-actin back to the profilin-ATP-actin pool ready for elongation of actin filaments.

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Organizational Affiliation: 
• Structural Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content 

• Total Structure Weight: 15.52 kDa 
• Atom Count: 1,168 
• Modeled Residue Count: 134 
• Deposited Residue Count: 137 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
ACTOPHORIN	A	137	Acanthamoeba polyphaga	Mutation(s): 0
UniProt
Find proteins for P37167 (Acanthamoeba castellanii) Explore P37167  Go to UniProtKB:  P37167

Small Molecules

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
SEP	A	L-PEPTIDE LINKING	C3 H8 N O6 P		SER

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.25 Å
• R-Value Free:  0.304 (Depositor) 
• R-Value Work:  0.204 (Depositor) 

Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 40.2	α = 90
b = 46.5	β = 90
c = 68.4	γ = 90

Software Package:

Software Name	Purpose
EPMR	phasing
REFMAC	refinement
DENZO	data reduction
SCALEPACK	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 1999-06-01 
Deposition Author(s): Blanchoin, L., Robinson, R.C., Choe, S., Pollard, T.D.

Revision History  

• Version 1.0: 1999-06-01
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2018-04-04
  Changes: Data collection
• Version 1.4: 2024-02-07
  Changes: Data collection, Database references
• Version 1.5: 2024-04-03
  Changes: Refinement description
• Version 1.6: 2024-11-06
  Changes: Structure summary