Correlation of cofactor binding and the quaternary structure of pyruvate decarboxylase as revealed by 31P NMR spectroscopy.
The pH dependence of the quaternary structure of pyruvate decarboxylase (EC 4.1.1.1) has recently been discovered [(1990) FEBS Lett. 266, 17-20; (1992) Biochemistry (in press)]. In the present study we have investigated the change in quaternary structure by observing the binding of the cofactor, thiamine pyrophosphate, using 31P NMR spectroscopy. The dissociation of the native tetramers into dimers when increasing the pH coincides with a weaker binding of the cofactor and loss of enzyme activity. The results provide further evidence that thiamine pyrophosphate is bound primarily via the beta-phosphate moiety. In addition, a phosphoserine has been discovered in two of the four subunits.
Hübner
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G
Martin-Luther University Halle-Wittenberg, Institute of Biochemistry, Germany.
König
S
S
Schnackerz
K D
KD
D001665:Binding Sites; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D010759:Phosphorus Isotopes; D011487:Protein Conformation; D011767:Pyruvate Decarboxylase / Q000187:drug effects / Q000378:metabolism*; D012440:Saccharomyces / Q000201:enzymology; D013835:Thiamine Pyrophosphate / Q000378:metabolism* / Q000494:pharmacology
D010759:Phosphorus Isotopes; D011767:Pyruvate Decarboxylase; D013835:Thiamine Pyrophosphate