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Updated: Mar 3, 2026

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Trapped intermediate state of plant pyruvate phosphate dikinase indicates substeps in catalytic swiveling domain
Alexander Minges1, Astrid Höppner2, Georg Groth1
1Cluster of Excellence on Plant Sciences (CEPLAS), Institute of Biochemical Plant Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, 40204, Germany.
Abstract:
Pyruvate phosphate dikinase (PPDK) is an essential enzyme of both the C4 photosynthetic pathway and cellular energy metabolism of some bacteria and unicellular protists. In C4 plants, it catalyzes the ATP- and Pi -dependent formation of phosphoenolpyruvate (PEP) while in bacteria and protozoa the ATP-forming direction is used. PPDK is composed out of three distinct domains and exhibits one of the largest single domain movements known today during its catalytic cycle. However, little information about potential intermediate steps of this movement was available. A recent study resolved a discrete intermediate step of PPDK's swiveling movement, shedding light on the details of this intriguing mechanism. Here we present an additional structural intermediate that possibly represents another crucial step in the catalytic cycle of PPDK, providing means to get a more detailed understanding of PPDK's mode of function.
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