Document Detail

Electrostatic interactions across the dimer-dimer interface contribute to the pH-dependent stability of a tetrameric malate dehydrogenase.
MedLine Citation:
PMID:  14572663     Owner:  NLM     Status:  MEDLINE    
Malate dehydrogenase (MDH) from the moderately thermophilic bacterium Chloroflexus aurantiacus (CaMDH) is a tetrameric enzyme, while MDHs from mesophilic bacteria usually are dimers. Using site-directed mutagenesis, we show here that a network of electrostatic interactions across the extra dimer-dimer interface in CaMDH is important for thermal stability and oligomeric integrity. Stability effects of single point mutations (E25Q, E25K, D56N, D56K) varied from -1.2 degrees C to -26.8 degrees C, and depended strongly on pH. Gel-filtration experiments indicated that the 26.8 degrees C loss in stability observed for the D56K mutant at low pH was accompanied by a shift towards a lower oligomerization state.
Alexandra Bjørk; Dimitrios Mantzilas; Reidun Sirevåg; Vincent G H Eijsink
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  FEBS letters     Volume:  553     ISSN:  0014-5793     ISO Abbreviation:  FEBS Lett.     Publication Date:  2003 Oct 
Date Detail:
Created Date:  2003-10-23     Completed Date:  2003-12-09     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0155157     Medline TA:  FEBS Lett     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  423-6     Citation Subset:  IM    
Department of Biology, University of Oslo, Box 1031 Blindern, N-0316 Oslo, Norway.
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MeSH Terms
Amino Acid Substitution
Bacterial Proteins / chemistry*
Chlorobi / enzymology
Chromatography, Gel
Enzyme Stability
Hot Temperature
Hydrogen-Ion Concentration
Malate Dehydrogenase / chemistry*
Models, Molecular
Mutagenesis, Site-Directed
Protein Conformation
Protein Denaturation
Protein Structure, Quaternary
Protein Subunits
Recombinant Proteins / chemistry
Static Electricity
Reg. No./Substance:
0/Bacterial Proteins; 0/Protein Subunits; 0/Recombinant Proteins; EC Dehydrogenase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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