4PCF

Structure-based protein engineering of a monomeric triosephosphate isomerase towards changing substrate specificity


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.71 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.235 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal structures of two monomeric triosephosphate isomerase variants identified via a directed-evolution protocol selecting for L-arabinose isomerase activity.

Krause, M.Kiema, T.R.Neubauer, P.Wierenga, R.K.

(2016) Acta Crystallogr.,Sect.F 72: 490-499

  • DOI: 10.1107/S2053230X16007548
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The crystal structures are described of two variants of A-TIM: Ma18 (2.7 Å resolution) and Ma21 (1.55 Å resolution). A-TIM is a monomeric loop-deletion variant of triosephosphate isomerase (TIM) which has lost the TIM catalytic properties. Ma18 and M ...

    The crystal structures are described of two variants of A-TIM: Ma18 (2.7 Å resolution) and Ma21 (1.55 Å resolution). A-TIM is a monomeric loop-deletion variant of triosephosphate isomerase (TIM) which has lost the TIM catalytic properties. Ma18 and Ma21 were identified after extensive directed-evolution selection experiments using an Escherichia coli L-arabinose isomerase knockout strain expressing a randomly mutated A-TIM gene. These variants facilitate better growth of the Escherichia coli selection strain in medium supplemented with 40 mM L-arabinose. Ma18 and Ma21 differ from A-TIM by four and one point mutations, respectively. Ma18 and Ma21 are more stable proteins than A-TIM, as judged from CD melting experiments. Like A-TIM, both proteins are monomeric in solution. In the Ma18 crystal structure loop 6 is open and in the Ma21 crystal structure loop 6 is closed, being stabilized by a bound glycolate molecule. The crystal structures show only small differences in the active site compared with A-TIM. In the case of Ma21 it is observed that the point mutation (Q65L) contributes to small structural rearrangements near Asn11 of loop 1, which correlate with different ligand-binding properties such as a loss of citrate binding in the active site. The Ma21 structure also shows that its Leu65 side chain is involved in van der Waals interactions with neighbouring hydrophobic side-chain moieties, correlating with its increased stability. The experimental data suggest that the increased stability and solubility properties of Ma21 and Ma18 compared with A-TIM cause better growth of the selection strain when coexpressing Ma21 and Ma18 instead of A-TIM.


    Organizational Affiliation

    Laboratory of Bioprocess Engineering, Department of Biotechnology, Technische Universität Berlin, Ackerstrasse 76, ACK 24, Berlin, Germany.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Ma18-TIM
A, B, C
239Trypanosoma brucei bruceiMutation(s): 0 
EC: 5.3.1.1
Find proteins for P04789 (Trypanosoma brucei brucei)
Go to UniProtKB:  P04789
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.71 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.235 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 92.920α = 90.00
b = 49.420β = 118.50
c = 95.510γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Academy of FinlandFinland117874
EMBO Shortterm FellowshipGermanyASTF 188-2011
FEBS Shortterm FellowshipGermany--

Revision History 

  • Version 1.0: 2015-04-22
    Type: Initial release
  • Version 1.1: 2016-06-29
    Type: Data collection, Database references