PDBsum entry 1tcd

Isomerase

PDB id: 1tcd

Contents

Protein chains

248 a.a. *

Waters ×165

* Residue conservation analysis

PDB id:

1tcd

Name:

Isomerase

Title:

Trypanosoma cruzi triosephosphate isomerase

Structure:

Triosephosphate isomerase. Chain: a, b. Synonym: tim. Engineered: yes

Source:

Trypanosoma cruzi. Organism_taxid: 5693. Strain: mexican ninoa. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Homo-Dimer (from PDB file)

Resolution:

1.83Å R-factor: 0.191 R-free: 0.258

Authors:

E.Maldonado,M.Soriano-Garcia,N.Cabrera,G.Garza-Ramos,M.Tuena De Gomez-Puyou,A.Gomez-Puyou,R.Perez-Montfort

Key ref:

E.Maldonado et al. (1998). Differences in the intersubunit contacts in triosephosphate isomerase from two closely related pathogenic trypanosomes. J Mol Biol, 283, 193-203. PubMed id: 9761683 DOI: 10.1006/jmbi.1998.2094

Date:

29-Jan-98 Release date: 13-Jan-99

Protein chains

P52270  (TPIS_TRYCR) -  Triosephosphate isomerase, glycosomal from Trypanosoma cruzi

Seq: 251 a.a.

Struc: 248 a.a.

Enzyme reactions

• Enzyme class: E.C.5.3.1.1 - triose-phosphate isomerase.
• Reaction: D-glyceraldehyde 3-phosphate = dihydroxyacetone phosphate

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1006/jmbi.1998.2094

J Mol Biol 283:193-203 (1998)

PubMed id: 9761683

Differences in the intersubunit contacts in triosephosphate isomerase from two closely related pathogenic trypanosomes.

E.Maldonado, M.Soriano-García, A.Moreno, N.Cabrera, G.Garza-Ramos, M.de Gómez-Puyou, A.Gómez-Puyou, R.Perez-Montfort.

ABSTRACT

The aligned amino acid sequences of TIM from Trypanosoma cruzi (TcTIM) and Trypanosoma brucei (TbTIM) have a positional identity of 68%. The two enzymes have markedly similar catalytic properties. Agents that interact with their interface Cys inhibit TcTIM and TbTIM; and those TIMs that lack this Cys (such as human TIM) are largely or completely insensitive to these agents. The susceptibility of TcTIM to the agents is approximately 100 times higher than that of TbTIM. To ascertain the cause of this large difference, the crystal structure of TcTIM was solved at 1.83 A resolution. The two enzymes are very similar homodimers. In TcTIM and TbTIM their respective Cys, 15 or 14, forms part of the dimer interface. In both, the contacts of the Cys with residues of the other subunit are almost identical. Nevertheless, there are noteworthy differences between the two; the existence of glutamine 18 in TbTIM instead of glutamic acid in TcTIM at the beginning of helix 1 decreases the contacts between this portion of the protein and helix 3 of the other subunit. In addition, TcTIM has proline at position 24 in the first helix of the TIM barrel; this is absent in the other TIM. Pro24 disrupts the regular helix arrangement, making the pitch of this helix 1.2 A longer than in TbTIM. When Pro24 of TcTIM was substituted for Glu, the sensitivity of TcTIM to sulfhydryl reagents increased about fivefold, possibly as a consequence of an increase in the space between the first portion of helix 1 and helix 3 of the other subunit. Therefore, it may be concluded that the geometry of the latter region is central in the accessibility to agents that perturb the interface Cys. In human TIM this region is more compact.

Selected figure(s)

Figure 2.
Figure 2. (a) Stereoview of the 3 F[o] -2 F[c]electron density map contoured at 1s of Cys15 of TcTIM and its surrounding loop 3 residues. (b) Stereoview of the interface Cys of TcTIM (orange) and TbTIM (green) and surrounding residues. The oxygen, nitrogen and sulfur atoms are represented in red, blue and yellow, respectively.

Figure 3.
Figure 3. Stereoview of the region between the end of loop 1 in monomer B and a portion of helix 3 of the adjoining subunit. TcTIM and TbTIM are depicted in orange and green, respectively. The color-code for the atoms is as in Figure 2(b).

The above figures are reprinted by permission from Elsevier: J Mol Biol (1998, 283, 193-203) copyright 1998.

Figures were selected by an automated process.