1B3B

THERMOTOGA MARITIMA GLUTAMATE DEHYDROGENASE MUTANT N97D, G376K


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.225 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Engineering activity and stability of Thermotoga maritima glutamate dehydrogenase. I. Introduction of a six-residue ion-pair network in the hinge region.

Lebbink, J.H.Knapp, S.van der Oost, J.Rice, D.Ladenstein, R.de Vos, W.M.

(1998) J.Mol.Biol. 280: 287-296

  • DOI: 10.1006/jmbi.1998.1870

  • PubMed Abstract: 
  • Comparison of the recently determined three-dimensional structures of several glutamate dehydrogenases allowed for the identification of a five-residue ion-pair network in the hinge region of Pyrococcus furiosus glutamate dehydrogenase (melting tempe ...

    Comparison of the recently determined three-dimensional structures of several glutamate dehydrogenases allowed for the identification of a five-residue ion-pair network in the hinge region of Pyrococcus furiosus glutamate dehydrogenase (melting temperature 113 degrees C), that is not present in the homologous glutamate dehydrogenase from Thermotoga maritima (melting temperature 93 degrees C). In order to study the role of this ion-pair network, we introduced it into the T. maritima enzyme using a site-directed mutagenesis approach. The resulting T. maritima glutamate dehydrogenases N97D, G376 K and N97D/G376 K as well as the wild-type enzyme were overproduced in Escherichia coli and subsequently purified. Elucidation of the three-dimensional structure of the double mutant N97D/G376 K at 3.0 A, showed that the designed ion-pair interactions were indeed formed. Moreover, because of interactions with an additional charged residue, a six-residue network is present in this double mutant. Melting temperatures of the mutant enzymes N97D, G376 K and N97D/G376 K, as determined by differential scanning calorimetry, did not differ significantly from that of the wild-type enzyme. Identical transition midpoints in guanidinium chloride-induced denaturation experiments were found for the wild-type and all mutant enzymes. Thermal inactivation at 85 degrees C occured more than twofold faster for all mutant enzymes than for the wild-type glutamate dehydrogenase. At temperatures of 65 degrees C and higher, the wild-type and the three mutant enzymes showed identical specific activities. However, at 58 degrees C the specific activity of N97D/G376 K and G376 K was found to be significantly higher than that of the wild-type and N97D enzymes. These results suggest that the engineered ion-pair interactions in the hinge region do not affect the stability towards temperature or guanidinium chloride-induced denaturation but rather affect the specific activity of the enzyme and the temperature at which it functions optimally.


    Organizational Affiliation

    Laboratory for Microbiology, Wageningen Agricultural University, Hesselink van Suchtelenweg 4, Wageningen, NL-6703 CT, The Netherlands.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PROTEIN (GLUTAMATE DEHYDROGENASE)
A, B, C, D, E, F
415Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099)Gene Names: gdhA (gdh)
EC: 1.4.1.3
Find proteins for P96110 (Thermotoga maritima (strain ATCC 43589 / MSB8 / DSM 3109 / JCM 10099))
Go to UniProtKB:  P96110
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.225 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 145.100α = 90.00
b = 145.100β = 90.00
c = 272.500γ = 120.00
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
DENZOdata reduction
X-PLORphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-12-08
    Type: Initial release
  • Version 1.1: 2008-04-26
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance