1VST

Symmetric Sulfolobus solfataricus uracil phosphoribosyltransferase with bound PRPP and GTP

1VST の概要

• エントリーDOI: 10.2210/pdb1vst/pdb
• 関連するPDBエントリー: 1XTT 1XTU 1XTV 3G6W
• 分子名称: Uracil phosphoribosyltransferase, GUANOSINE-5'-TRIPHOSPHATE, MAGNESIUM ION, ... (5 entities in total)
• 機能のキーワード: uracil, phosphoribosyltransferase, allosteric regulation, sulfolobus solfataricus, prpp, gtp, glycosyltransferase, magnesium, transferase
• 由来する生物種: Sulfolobus solfataricus
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 25116.90

構造登録者

Kadziola, A. (登録日: 2009-02-09, 公開日: 2009-09-01, 最終更新日: 2023-10-25)

主引用文献

Christoffersen, S.,Kadziola, A.,Johansson, E.,Rasmussen, M.,Willemoes, M.,Jensen, K.F.
Structural and kinetic studies of the allosteric transition in Sulfolobus solfataricus uracil phosphoribosyltransferase: Permanent activation by engineering of the C-terminus
J.Mol.Biol., 393:464-477, 2009

PubMed Abstract: Uracil phosphoribosyltransferase catalyzes the conversion of 5-phosphoribosyl-alpha-1-diphosphate (PRPP) and uracil to uridine monophosphate (UMP) and diphosphate (PP(i)). The tetrameric enzyme from Sulfolobus solfataricus has a unique type of allosteric regulation by cytidine triphosphate (CTP) and guanosine triphosphate (GTP). Here we report two structures of the activated state in complex with GTP. One structure (refined at 2.8-A resolution) contains PRPP in all active sites, while the other structure (refined at 2.9-A resolution) has PRPP in two sites and the hydrolysis products, ribose-5-phosphate and PP(i), in the other sites. Combined with three existing structures of uracil phosphoribosyltransferase in complex with UMP and the allosteric inhibitor cytidine triphosphate (CTP), these structures provide valuable insight into the mechanism of allosteric transition from inhibited to active enzyme. The regulatory triphosphates bind at a site in the center of the tetramer in a different manner and change the quaternary arrangement. Both effectors contact Pro94 at the beginning of a long beta-strand in the dimer interface, which extends into a flexible loop over the active site. In the GTP-bound state, two flexible loop residues, Tyr123 and Lys125, bind the PP(i) moiety of PRPP in the neighboring subunit and contribute to catalysis, while in the inhibited state, they contribute to the configuration of the active site for UMP rather than PRPP binding. The C-terminal Gly216 participates in a hydrogen-bond network in the dimer interface that stabilizes the inhibited, but not the activated, state. Tagging the C-terminus with additional amino acids generates an endogenously activated enzyme that binds GTP without effects on activity.

PubMed: 19683539
DOI: 10.1016/j.jmb.2009.08.019

実験手法

X-RAY DIFFRACTION (2.8 Å)