6CJZ

Solution Structure of Amebosin

PDB DOI: 10.2210/pdb6CJZ/pdb
BMRB: 30418

Classification: PROTEIN FIBRIL
Organism(s): Entamoeba histolytica
Expression System: Escherichia coli
Mutation(s): Yes

Deposited: 2018-02-27 Released: 2019-02-06
Deposition Author(s): Mendoza, A., Flores-Solis, D., Del Rio Portilla, F., Brieba de Castro, L.
Funding Organization(s): DGAPA

Experimental Data Snapshot

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

wwPDB Validation 3D Report Full Report

This is version 1.1 of the entry. See complete history.

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

PubMed: 32731033 Search on PubMed
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 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) | 3D Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Amoebiasin-1	A	105	Entamoeba histolytica	Mutation(s): 3 Gene Names: AMS, ICP1
UniProt
Find proteins for Q6KCA4 (Entamoeba histolytica) Explore Q6KCA4 Go to UniProtKB: Q6KCA4
Entity Groups
Sequence Clusters	30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt Group	Q6KCA4
Protein Feature View Expand
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