Cold-adaptation mechanism of mutant enzymes of 3-isopropylmalate dehydrogenase from Thermus thermophilus.


Abstract

Random mutagenesis of Thermus thermophilus 3-isopropylmalate dehydrogenase revealed that a substitution of Val126Met in a hinge region caused a marked increase in specific activity, particularly at low temperatures, although the site is far from the binding residues for 3-isopropylmalate and NAD. To understand the molecular mechanism, residue 126 was substituted with one of eight other residues, Gly, Ala, Ser, Thr, Glu, Leu, Ile or Phe. Circular dichroism analyses revealed a decreased thermal stability of the mutants (Delta T ((1/2))= 0-13 degrees C), indicating structural perturbations caused by steric conflict with surrounding residues having larger side chains. Kinetic parameters, k(cat) and K(m) values for isopropylmalate and NAD, were also affected by the mutation, but the resulting k(cat)/K(m) values were similar to that of the wild-type enzyme, suggesting that the change in the catalytic property is caused by the change in free-energy level of the Michaelis complex state relative to that of the initial state. The kinetic parameters and activation enthalpy change (Delta H (double dagger)) showed good correlation with the van der Waals volume of residue 126. These results suggested that the artificial cold adaptation (enhancement of k(cat) value at low temperatures) resulted from the destabilization of the ternary complex caused by the increase in the volume of the residue at position 126. Study holds ProTherm entries: 15168, 15169, 15170, 15171, 15172, 15173, 15174, 15175, 15176 Extra Details: cold adaptation; 3-isopropylmalate dehydrogenase; mutagenesis; thermophile enzyme

Submission Details

ID: dhu8NWVP

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:45 p.m.

Version: 1

Publication Details
Suzuki T;Yasugi M;Arisaka F;Oshima T;Yamagishi A,Protein Eng. (2002) Cold-adaptation mechanism of mutant enzymes of 3-isopropylmalate dehydrogenase from Thermus thermophilus. PMID:12082165
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
2Y3Z 2011-01-19 1.83 Structure of Isopropylmalate dehydrogenase from Thermus thermophilus - apo enzyme
4F7I 2012-06-13 2.0 Structure of Isopropylmalate dehydrogenase from Thermus thermophilus in complex with IPM, Mn and NADH
4WUO 2014-11-12 2.05 Structure of the E270A Mutant Isopropylmalate dehydrogenase from Thermus thermophilus in complex with IPM, Mn and NADH
1G2U 2000-11-01 2.1 THE STRUCTURE OF THE MUTANT, A172V, OF 3-ISOPROPYLMALATE DEHYDROGENASE FROM THERMUS THERMOPHILUS HB8 : ITS THERMOSTABILITY AND STRUCTURE.
1XAA 1996-04-03 2.1 3-ISOPROPYLMALATE DEHYDROGENASE, LOW TEMPERATURE (100K) STRUCTURE
1XAD 1996-04-03 2.1 CHIMERA ISOPROPYLMALATE DEHYDROGENASE BETWEEN BACILLUS SUBTILIS (M) AND THERMUS THERMOPHILUS (T) FROM N-TERMINAL: 20% T MIDDLE 20% M RESIDUAL 60% T, MUTATED AT S82R. LOW TEMPERATURE (150K) STRUCTURE.
1XAB 1996-04-03 2.1 3-ISOPROPYLMALATE DEHYDROGENASE, LOW TEMPERATURE (150K) STRUCTURE
1XAC 1996-04-03 2.1 CHIMERA ISOPROPYLMALATE DEHYDROGENASE BETWEEN BACILLUS SUBTILIS (M) AND THERMUS THERMOPHILUS (T) FROM N-TERMINAL: 20% T MIDDLE 20% M RESIDUAL 60% T, MUTATED AT S82R. LOW TEMPERATURE (100K) STRUCTURE.
1IDM 1995-09-15 2.2 3-ISOPROPYLMALATE DEHYDROGENASE, LOOP-DELETED CHIMERA
1DR0 2000-01-19 2.2 STRUCTURE OF MODIFIED 3-ISOPROPYLMALATE DEHYDROGENASE AT THE C-TERMINUS, HD708
1IPD 1993-10-31 2.2 THREE-DIMENSIONAL STRUCTURE OF A HIGHLY THERMOSTABLE ENZYME, 3-ISOPROPYLMALATE DEHYDROGENASE OF THERMUS THERMOPHILUS AT 2.2 ANGSTROMS RESOLUTION
2Y41 2011-01-19 2.2 Structure of Isopropylmalate dehydrogenase from Thermus thermophilus - complex with IPM and MN
1WAL 1999-05-25 2.27 3-ISOPROPYLMALATE DEHYDROGENASE (IPMDH) MUTANT (M219A)FROM THERMUS THERMOPHILUS
1GC9 2000-09-27 2.3 THE CRYSTAL STRUCTURE OF THERMUS THERMOPHILUS 3-ISOPROPYLMALATE DEHYDROGENASE MUTATED AT 172TH FROM ALA TO GLY
1OSJ 1997-01-27 2.35 STRUCTURE OF 3-ISOPROPYLMALATE DEHYDROGENASE
1HEX 1994-12-20 2.5 STRUCTURE OF 3-ISOPROPYLMALATE DEHYDROGENASE IN COMPLEX WITH NAD+: LIGAND-INDUCED LOOP-CLOSING AND MECHANISM FOR COFACTOR SPECIFICITY
2Y40 2011-01-19 2.5 Structure of Isopropylmalate dehydrogenase from Thermus thermophilus - complex with Mn
1GC8 2000-09-27 2.5 THE CRYSTAL STRUCTURE OF THERMUS THERMOPHILUS 3-ISOPROPYLMALATE DEHYDROGENASE MUTATED AT 172TH FROM ALA TO PHE
2Y42 2011-01-19 2.5 Structure of Isopropylmalate dehydrogenase from Thermus thermophilus - complex with NADH and Mn
1DR8 2000-01-19 2.7 STRUCTURE OF MODIFIED 3-ISOPROPYLMALATE DEHYDROGENASE AT THE C-TERMINUS, HD177
2ZTW 2009-10-13 2.79 Structure of 3-isopropylmalate dehydrogenase in complex with the inhibitor and NAD+
1DPZ 2000-01-12 2.8 STRUCTURE OF MODIFIED 3-ISOPROPYLMALATE DEHYDROGENASE AT THE C-TERMINUS, HD711
1OSI 1997-01-27 3.0 STRUCTURE OF 3-ISOPROPYLMALATE DEHYDROGENASE

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
91.9 3-isopropylmalate dehydrogenase P24098 LEU3_THEAQ
100.0 3-isopropylmalate dehydrogenase P61495 LEU3_THETH
99.4 3-isopropylmalate dehydrogenase P61494 LEU3_THET2
100.0 3-isopropylmalate dehydrogenase Q5SIY4 LEU3_THET8