PDBsum entry 1mss

Isomerase(intramolecular oxidoreductase)

PDB id: 1mss

Contents

Protein chains

242 a.a. *

Waters ×56

* Residue conservation analysis

PDB id:

1mss

Name:

Isomerase(intramolecular oxidoreductase)

Title:

Large scale structural rearrangements of the front loops in monomerised triosephosphate isomerase, as deduced from the comparison of the structural properties of monotim and its point mutation variant monoss

Structure:

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

Source:

Trypanosoma brucei brucei. Organism_taxid: 5702. Strain: brucei

Biol. unit:

Dimer (from PQS)

Resolution:

2.40Å R-factor: 0.198

Authors:

K.V.Radha Kishan,R.K.Wierenga

Key ref:

T.V.Borchert et al. (1995). Three new crystal structures of point mutation variants of monoTIM: conformational flexibility of loop-1, loop-4 and loop-8. Structure, 3, 669-679. PubMed id: 8591044 DOI: 10.1016/S0969-2126(01)00202-7

Date:

27-Jul-94 Release date: 30-Sep-94

Protein chains

P04789  (TPIS_TRYBB) -  Triosephosphate isomerase, glycosomal from Trypanosoma brucei brucei

Seq: 250 a.a.

Struc: 242 a.a.*

* PDB and UniProt seqs differ at 9 residue positions (black crosses)

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: 10.1016/S0969-2126(01)00202-7

Structure 3:669-679 (1995)

PubMed id: 8591044

Three new crystal structures of point mutation variants of monoTIM: conformational flexibility of loop-1, loop-4 and loop-8.

T.V.Borchert, K.V.Kishan, J.P.Zeelen, W.Schliebs, N.Thanki, R.Abagyan, R.Jaenicke, R.K.Wierenga.

ABSTRACT

BACKGROUND: Wild-type triosephosphate isomerase (TIM) is a very stable dimeric enzyme. This dimer can be converted into a stable monomeric protein (monoTIM) by replacing the 15-residue interface loop (loop-3) by a shorter, 8-residue, loop. The crystal structure of monoTIM shows that two active-site loops (loop-1 and loop-4), which are at the dimer interface in wild-type TIM, have acquired rather different structural properties. Nevertheless, monoTIM has residual catalytic activity. RESULTS: Three new structures of variants of monoTIM are presented, a double-point mutant crystallized in the presence and absence of bound inhibitor, and a single-point mutant in the presence of a different inhibitor. These new structures show large structural variability for the active-site loops, loop-1, loop-4 and loop-8. In the structures with inhibitor bound, the catalytic lysine (Lys13 in loop-1) and the catalytic histidine (His95 in loop-4) adopt conformations similar to those observed in wild-type TIM, but very different from the monoTIM structure. CONCLUSIONS: The residual catalytic activity of monoTIM can now be rationalized. In the presence of substrate analogues the active-site loops, loop-1, loop-4 and loop-8, as well as the catalytic residues, adopt conformations similar to those seen in the wild-type protein. These loops lack conformational flexibility in wild-type TIM. The data suggest that the rigidity of these loops in wild-type TIM, resulting from subunit-subunit contacts at the dimer interface, is important for optimal catalysis.

Selected figure(s)

Figure 1.
Figure 1. (a) The reaction catalyzed by TIM. (b) The structures of two inhibitors of TIM, PGH and 2PG. Figure 1. (a) The reaction catalyzed by TIM. (b) The structures of two inhibitors of TIM, PGH and 2PG.

Figure 4.
Figure 4. Comparison of monoTIM-SS (red), monoTIM (green) and wtTIM (yellow). (a) The complete Cα traces. One residue of each front loop of monoTIM is labelled: Trp12 (L1), Phe45 (L2), Ala70 (L3), His95 (L4), Glu129 (L5), Val169 (L6), Gly212 (L7) and Gly235 (L8). Also shown, in green, is the sulphate ion, near loop-6, loop-7 and loop-8, as observed in the monoTIM structure. (b) Comparison of the Cα traces near L8, L1, L2 and L3. The side chains of residues Ser237 (L8), Trp12 (L1), Thr44 (L2) and Gln65 (L3) are also shown. Figure 4. Comparison of monoTIM-SS (red), monoTIM (green) and wtTIM (yellow). (a) The complete Cα traces. One residue of each front loop of monoTIM is labelled: Trp12 (L1), Phe45 (L2), Ala70 (L3), His95 (L4), Glu129 (L5), Val169 (L6), Gly212 (L7) and Gly235 (L8). Also shown, in green, is the sulphate ion, near loop-6, loop-7 and loop-8, as observed in the monoTIM structure. (b) Comparison of the Cα traces near L8, L1, L2 and L3. The side chains of residues Ser237 (L8), Trp12 (L1), Thr44 (L2) and Gln65 (L3) are also shown.

The above figures are reprinted by permission from Cell Press: Structure (1995, 3, 669-679) copyright 1995.

Figures were selected by an automated process.