Electrostatic interactions across the dimer-dimer interface contribute to the pH-dependent stability of a tetrameric malate dehydrogenase
In: FEBS Letters, Jg. 553 (2003-10-02), S. 423-426
Online
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Zugriff:
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.
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Electrostatic interactions across the dimer-dimer interface contribute to the pH-dependent stability of a tetrameric malate dehydrogenase
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Autor/in / Beteiligte Person: | Mantzilas, Dimitrios ; Sirevåg, Reidun ; Eijsink, Vincent G. H. ; Bjørk, Alexandra |
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Zeitschrift: | FEBS Letters, Jg. 553 (2003-10-02), S. 423-426 |
Veröffentlichung: | Wiley, 2003 |
Medientyp: | unknown |
ISSN: | 0014-5793 (print) |
DOI: | 10.1016/s0014-5793(03)01076-7 |
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