PDBsum entry 2fo8

Hydrolase inhibitor

PDB id: 2fo8

Contents

Protein chain

108 a.a. *

* Residue conservation analysis

PDB id:

2fo8

Name:

Hydrolase inhibitor

Title:

Solution structure of the trypanosoma cruzi cysteine protease inhibitor chagasin

Structure:

Chagasin. Chain: a. Engineered: yes

Source:

Trypanosoma cruzi. Organism_taxid: 5693. Strain: dm28c. Gene: cha. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

15 models

Authors:

D.Salmon,R.Do Aido-Machado,A.A.P.De Lima,J.Scharfstein,H.Oschkinat, J.R.Pires

Key ref:

D.Salmon et al. (2006). Solution structure and backbone dynamics of the Trypanosoma cruzi cysteine protease inhibitor chagasin. J Mol Biol, 357, 1511-1521. PubMed id: 16490204 DOI: 10.1016/j.jmb.2006.01.064

Date:

13-Jan-06 Release date: 04-Apr-06

Protein chain

Q966X9  (CHAG_TRYCR) -  Chagasin from Trypanosoma cruzi

Seq: 110 a.a.

Struc: 108 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1016/j.jmb.2006.01.064

J Mol Biol 357:1511-1521 (2006)

PubMed id: 16490204

Solution structure and backbone dynamics of the Trypanosoma cruzi cysteine protease inhibitor chagasin.

D.Salmon, R.do Aido-Machado, A.Diehl, M.Leidert, O.Schmetzer, A.P.de A Lima, J.Scharfstein, H.Oschkinat, J.R.Pires.

ABSTRACT

A Trypanosoma cruzi cysteine protease inhibitor, termed chagasin, is the first characterized member of a new family of tight-binding cysteine protease inhibitors identified in several lower eukaryotes and prokaryotes but not present in mammals. In the protozoan parasite T.cruzi, chagasin plays a role in parasite differentiation and in mammalian host cell invasion, due to its ability to modulate the endogenous activity of cruzipain, a lysosomal-like cysteine protease. In the present work, we determined the solution structure of chagasin and studied its backbone dynamics by NMR techniques. Structured as a single immunoglobulin-like domain in solution, chagasin exerts its inhibitory activity on cruzipain through conserved residues placed in three loops in the same side of the structure. One of these three loops, L4, predicted to be of variable length among chagasin homologues, is flexible in solution as determined by measurements of (15)N relaxation. The biological implications of structural homology between chagasin and other members of the immunoglobulin super-family are discussed.

Selected figure(s)

Figure 3.
Figure 3. Solution NMR structure of the T. cruzi chagasin (stereo view). (a) Superposition of the backbone atoms for the 15 lowest-energy structures of chagasin, residues 3-110. b-Strands (b1-b8), 3[10]-helix, and loops (L1-L6) are coloured blue, green and red, respectively. Selected residue side-chains are displayed and labelled. The structural statistics are given in Table 1. (b) Ribbon diagram of the chagasin lowest-energy structure. The colouring scheme is the same as in (a).

Figure 5.
Figure 5. Dynamics from NMR data. (a) 1H-15N heteronuclear NOE data. (b) 15N R[2] relaxation data. (c) 15N R[1] relaxation data. Slowly relaxing, flexible loop L4 is marked. b-Strands, 3[10]-helix and loops are indicated schematically.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2006, 357, 1511-1521) copyright 2006.

Figures were selected by an automated process.