title: Crystal structures of pyruvate phosphate dikinase from maize revealed an alternative conformation in the swiveling-domain motion.
abstract: Pyruvate phosphate dikinase (PPDK) reversibly catalyzes the conversion of ATP, phosphate, and pyruvate into AMP, pyrophosphate, and phosphoenolpyruvate (PEP), respectively. Since the nucleotide binding site (in the N-terminal domain) and the pyruvate/PEP binding site (in the C-terminal domain) are separated by approximately 45 A, it has been proposed that an intermediary domain, called the central domain, swivels between these remote domains to transfer the phosphate. However, no direct structural evidence for the swiveling central domain has been found. In this study, the crystal structures of maize PPDK with and without PEP have been determined at 2.3 A resolution. These structures revealed that the central domain is located near the pyruvate/PEP binding C-terminal domain, in contrast to the PPDK from Clostridium symbiosum, wherein the central domain is located near the nucleotide-binding N-terminal domain. Structural comparisons between the maize and C. symbiosum PPDKs demonstrated that the swiveling motion of the central domain consists of a rotation of at least 92 degrees and a translation of 0.5 A. By comparing the maize PPDK structures with and without PEP, we have elucidated the mode of binding of PEP to the C-terminal domain and the induced conformational changes in the central domain.
authors.affiliation: Kinetic Crystallography Research Team, Membrane Dynamics Research Group, RIKEN Harima Institute at SPring-8, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan.
authors.forename: Tsugumi
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Toru
authors.initials: T
authors.lastname: Nakatsu
authors.forename: Makoto
authors.initials: M
authors.lastname: Matsuoka
authors.forename: Kanzo
authors.initials: K
authors.lastname: Sakata
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kato
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002384:Catalysis; D003198:Computer Simulation; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010728:Phosphoenolpyruvate / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011772:Pyruvate, Orthophosphate Dikinase / Q000737:chemistry* / Q000378:metabolism; D013379:Substrate Specificity; D013816:Thermodynamics; D003313:Zea mays / Q000201:enzymology*
chemical_list: D008024:Ligands; D010940:Plant Proteins; D010728:Phosphoenolpyruvate; C037396:PPDK protein, Zea mays; D011772:Pyruvate, Orthophosphate Dikinase