4OCI

Crystal Structure of Calcium Binding Protein-5 from Entamoeba histolytica and its involvement in initiation of phagocytosis of human erythrocytes


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.01 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.181 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Crystal Structure of Calcium Binding Protein-5 from Entamoeba histolytica and Its Involvement in Initiation of Phagocytosis of Human Erythrocytes.

Kumar, S.Aslam, S.Mazumder, M.Dahiya, P.Murmu, A.Manjasetty, B.A.Zaidi, R.Bhattacharya, A.Gourinath, S.

(2014) PLoS Pathog 10: e1004532-e1004532

  • DOI: 10.1371/journal.ppat.1004532
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • Entamoeba histolytica is the etiological agent of human amoebic colitis and liver abscess, and causes a high level of morbidity and mortality worldwide, particularly in developing countries. There are a number of studies that have shown a crucial rol ...

    Entamoeba histolytica is the etiological agent of human amoebic colitis and liver abscess, and causes a high level of morbidity and mortality worldwide, particularly in developing countries. There are a number of studies that have shown a crucial role for Ca2+ and its binding protein in amoebic biology. EhCaBP5 is one of the EF hand calcium-binding proteins of E. histolytica. We have determined the crystal structure of EhCaBP5 at 1.9 Å resolution in the Ca2+-bound state, which shows an unconventional mode of Ca2+ binding involving coordination to a closed yet canonical EF-hand motif. Structurally, EhCaBP5 is more similar to the essential light chain of myosin than to Calmodulin despite its somewhat greater sequence identity with Calmodulin. This structure-based analysis suggests that EhCaBP5 could be a light chain of myosin. Surface plasmon resonance studies confirmed this hypothesis, and in particular showed that EhCaBP5 interacts with the IQ motif of myosin 1B in calcium independent manner. It also appears from modelling of the EhCaBP5-IQ motif complex that EhCaBP5 undergoes a structural change in order to bind the IQ motif of myosin. This specific interaction was further confirmed by the observation that EhCaBP5 and myosin 1B are colocalized in E. histolytica during phagocytic cup formation. Immunoprecipitation of EhCaBP5 from total E. histolytica cellular extract also pulls out myosin 1B and this interaction was confirmed to be Ca2+ independent. Confocal imaging of E. histolytica showed that EhCaBP5 and myosin 1B are part of phagosomes. Overexpression of EhCaBP5 increases slight rate (∼20%) of phagosome formation, while suppression reduces the rate drastically (∼55%). Taken together, these experiments indicate that EhCaBP5 is likely to be the light chain of myosin 1B. Interestingly, EhCaBP5 is not present in the phagosome after its formation suggesting EhCaBP5 may be playing a regulatory role.


    Organizational Affiliation

    School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Calmodulin, putativeA146Entamoeba histolytica HM-1:IMSS-AMutation(s): 0 
Gene Names: CaBP5EHI7A_088180
Find proteins for N9UIU7 (Entamoeba histolytica HM-1:IMSS-A)
Explore N9UIU7 
Go to UniProtKB:  N9UIU7
Protein Feature View
 ( Mouse scroll to zoom / Hold left click to move )
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download CCD File 
A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
CA
Query on CA

Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
NA
Query on NA

Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
AL-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.01 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.181 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.552α = 90
b = 44.446β = 108.92
c = 47.73γ = 90
Software Package:
Software NamePurpose
SHELXphasing
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
DENZOdata reduction
SCALEPACKdata scaling
HKL-2000data scaling
SHELXDphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-12-24
    Type: Initial release
  • Version 1.1: 2017-11-22
    Changes: Refinement description