6CJZ

Solution Structure of Amebosin


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 10 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum 

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Literature

Solution structure of the inhibitor of cysteine proteases 1 from Entamoeba histolytica reveals a possible auto regulatory mechanism.

Flores-Solis, D.Mendoza, A.Renteria-Gonzalez, I.Casados-Vazquez, L.E.Trasvina-Arenas, C.H.Jimenez-Sandoval, P.Benitez-Cardoza, C.G.Del Rio-Portilla, F.Brieba, L.G.

(2020) Biochim Biophys Acta Proteins Proteom 1868: 140512-140512

  • DOI: 10.1016/j.bbapap.2020.140512
  • Primary Citation of Related Structures:  
    6CJZ

  • PubMed Abstract: 
  • The genome of Entamoeba histolytica encodes approximately 50 Cysteine Proteases (CPs) whose activity is regulated by two Inhibitors of Cysteine Proteases (ICPs), EhICP1 and EhICP2. The main difference between both EhICPs is the acquisition of a 17 N-terminal targeting signal in EhICP2 and three exposed cysteine residues in EhICP1 ...

    The genome of Entamoeba histolytica encodes approximately 50 Cysteine Proteases (CPs) whose activity is regulated by two Inhibitors of Cysteine Proteases (ICPs), EhICP1 and EhICP2. The main difference between both EhICPs is the acquisition of a 17 N-terminal targeting signal in EhICP2 and three exposed cysteine residues in EhICP1. The three exposed cysteines in EhICP1 potentiate the formation of cross-linking species that drive heterogeneity. Here we solved the NMR structure of EhICP1 using a mutant protein without accessible cysteines. Our structural data shows that EhICP1 adopts an immunoglobulin fold composed of seven β-strands, and three solvent exposed loops that resemble the structures of EhICP2 and chagasin. EhICP1 and EhICP2 are able to inhibit the archetypical cysteine protease papain by intercalating their BC loops into the protease active site independently of the character of the residue (serine or threonine) responsible to interact with the active site of papain. EhICP1 and EhICP2 present signals of functional divergence as they clustered in different clades. Two of the three exposed cysteines in EhICP1 are located at the DE loop that intercalates into the CP substrate-binding cleft. We propose that the solvent exposed cysteines of EhICP1 play a role in regulating its inhibitory activity and that in oxidative conditions, the cysteines of EhICP1 react to form intra and intermolecular disulfide bonds that render an inactive inhibitor. EhICP2 is not subject to redox regulation, as this inhibitor does not contain a single cysteine residue. This proposed redox regulation may be related to the differential cellular localization between EhICP1 and EhICP2.


    Organizational Affiliation

    Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, km. 9.6 Libramiento Norte Carretera Irapuato-León, CP 36821 Irapuato, Guanajuato, Mexico. Electronic address: luis.brieba@cinvestav.mx.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Amoebiasin-1A105Entamoeba histolyticaMutation(s): 3 
Gene Names: AMSICP1
UniProt
Find proteins for Q6KCA4 (Entamoeba histolytica)
Explore Q6KCA4 
Go to UniProtKB:  Q6KCA4
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 10 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum 
  • OLDERADO: 6CJZ Olderado

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
DGAPAMexico207516

Revision History  (Full details and data files)

  • Version 1.0: 2019-02-06
    Type: Initial release
  • Version 1.1: 2020-08-19
    Changes: Data collection, Database references