Affinity shift of ATP upon glycerol binding to a glycerol kinase from the hyperthermophilic archaeon Thermococcus kodakarensis KOD1

Publication date: Available online 31 January 2020Source: Journal of Bioscience and BioengineeringAuthor(s): Ryuta Hokao, Hiroyoshi Matsumura, Ryota Katsumi, Clement Angkawidjaja, Kazufumi Takano, Shigenori Kanaya, Yuichi KogaGlycerol kinase (GK) is a key enzyme of glycerol metabolism. It participates in glycolysis and lipid membrane biosynthesis. A hexamer of GK from the hyperthermophilic archaeon Thermococcus kodakarensis KOD1(Tk-GK) was identified as a substrate-binding form of the enzyme. Here, the X-ray crystal structure analysis and the biochemical analysis was done and the relationships between its unique oligomer structure and substrate binding affinity were investigated. Wild type GK and mutant K271E GK, which disrupts the hexamer formation interface, were crystallized with and without their substrates and analyzed at 2.19–3.05 Å resolution. In the absence of glycerol, Tk-GK was a dimer in solution. In the presence of its glycerol substrate, however, it became a hexamer consisting of three symmetrical dimers about the threefold axis. Through glycerol binding, all Tk-GK molecules in the hexamer were in closed form as a result of domain-motion. The closed form of Tk-GK had tenfold higher ATP affinity than the open form of Tk-GK. The hexamer structure stabilized the closed conformation and enhanced ATP binding affinity when the GK was bound to glycerol. This molecular mechanism is quite simple activity regulation mechanism among known GKs.

Source: Journal of Bioscience and Bioengineering - January 31, 2020 Category: Biomedical Science Source Type: research