Biological Assembly 1  

 3D View: Structure | 1D-3D View | Validation Report | Ligand Interaction

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

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 23.11 kDa 
• Atom Count: 1677 
• Modelled Residue Count: 215 
• Deposited Residue Count: 215 
• Unique protein chains: 1

2AIM

CRUZAIN INHIBITED WITH BENZOYL-ARGININE-ALANINE-FLUOROMETHYLKETONE

• PDB DOI: 10.2210/pdb2AIM/pdb

• Classification: HYDROLASE/HYDROLASE INHIBITOR
• Organism(s): Trypanosoma cruzi
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 1997-04-21 Released: 1997-10-22 
• Deposition Author(s): Gillmor, S.A., Fletterick, R.J.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.20 Å
• R-Value Free: 0.249 
• R-Value Work: 0.186 
• R-Value Observed: 0.186 

Literature

Structural determinants of specificity in the cysteine protease cruzain.

Gillmor, S.A., Craik, C.S., Fletterick, R.J.

(1997) Protein Sci 6: 1603-1611

• PubMed: 9260273 
• DOI: 10.1002/pro.5560060801
• Primary Citation of Related Structures:  
  1AIM, 2AIM


• PubMed Abstract: 
  

The structure of cruzain, an essential protease from the parasite Trypanosoma cruzi, was determined by X-ray crystallography bound to two different covalent inhibitors. The cruzain S2 specificity pocket is able to productively bind both arginine and phenylalanine residues. The structures of cruzain bound to benzoyl-Arg-Ala-fluoromethyl ketone and benzoyl-Tyr-Ala-fluoromethyl ketone at 2.2 and 2.1 A, respectively, show a pH-dependent specificity switch. Glu 205 adjusts to restructure the S2 specificity pocket, conferring right binding to both hydrophobic and basic residues. Kinetic analysis of activated peptide substrates shows that substrates placing hydrophobic residues in the specificity pocket are cleaved at a broader pH range than hydrophilic substrates. These results demonstrate how cruzain binds both basic and hydrophobic residues and could be important for in vivo regulation of cruzain activity.

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Related Citations: 

• The Crystal Structure of Cruzain: A Therapeutic Target for Chagas' Disease
  Mcgrath, M.E., Eakin, A.E., Engel, J.C., Mckerrow, J.H., Craik, C.S., Fletterick, R.J.
  (1995) J Mol Biol 247: 251

• Production of Crystallizable Cruzain, the Major Cysteine Protease from Trypanosoma Cruzi
  Eakin, A.E., Mcgrath, M.E., Mckerrow, J.H., Fletterick, R.J., Craik, C.S.
  (1993) J Biol Chem 268: 6115

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Organizational Affiliation: 

Graduate Group in Biophysics, University of California, San Francisco 94143-0448, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
CRUZAIN	A	215	Trypanosoma cruzi	Mutation(s): 0  EC: 3.4.22 (PDB Primary Data), 3.4.22.51 (UniProt)
UniProt
Find proteins for P25779 (Trypanosoma cruzi) Explore P25779  Go to UniProtKB:  P25779

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ZRA	B [auth A]	BENZOYL-ARGININE-ALANINE-FLUORO-METHYL KETONE C18 H28 F N5 O4 FAAPWXRBXXSQNJ-JSGCOSHPSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.20 Å
• R-Value Free: 0.249 
• R-Value Work: 0.186 
• R-Value Observed: 0.186 
• Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 43.16	α = 90
b = 51.6	β = 115.2
c = 45.2	γ = 90

Software Package:

Software Name	Purpose
UCSD	data collection
UCSD	data reduction
X-PLOR	model building
X-PLOR	refinement
UCSD	data scaling
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1997-04-21 
• Released Date: 1997-10-22 
Deposition Author(s): Gillmor, S.A., Fletterick, R.J.

Revision History  

• Version 1.0: 1997-10-22
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Atomic model, Database references, Derived calculations, Non-polymer description, Structure summary, Version format compliance