1TDA

STRUCTURES OF THYMIDYLATE SYNTHASE WITH A C-TERMINAL DELETION: ROLE OF THE C-TERMINUS IN ALIGNMENT OF D/UMP AND CH2H4FOLATE

1TDA の概要

• エントリーDOI: 10.2210/pdb1tda/pdb
• 分子名称: THYMIDYLATE SYNTHASE, PHOSPHATE ION (3 entities in total)
• 機能のキーワード: transferase (methyltransferase)
• 由来する生物種: Lactobacillus casei
• 細胞内の位置: Cytoplasm: P00469
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 36626.29

構造登録者

Perry, K.M.,Carreras, C.W.,Chang, L.C.,Santi, D.V.,Stroud, R.M. (登録日: 1993-02-15, 公開日: 1993-07-15, 最終更新日: 2024-02-14)

主引用文献

Perry, K.M.,Carreras, C.W.,Chang, L.C.,Santi, D.V.,Stroud, R.M.
Structures of thymidylate synthase with a C-terminal deletion: role of the C-terminus in alignment of 2'-deoxyuridine 5'-monophosphate and 5,10-methylenetetrahydrofolate.
Biochemistry, 32:7116-7125, 1993

PubMed Abstract: Thymidylate synthase undergoes a major conformational change upon ligand binding, where the carboxyl terminus displays the largest movement (approximately 4 A). This movement from an "open" unliganded state to the "closed" complexed conformation plays a crucial role in the correct orientation of substrates and in product formation. The mutant lacking the C-terminal valine (V316Am) of the enzyme is inactive. X-ray crystal structures of V316Am and its complexes with dUMP, FdUMP, and both FdUMP and CH2H4folate are described. The structures show that ligands are bound within the active site, but in different modes than those in analogous, wild-type thymidylate synthase structures. The 2.7-A binary complex structures of V316Am with FdUMP and dUMP show that the pyrimidine and ribose moieties of the nucleotides are pivoted approximately 20 degrees around the 3'-hydroxyl compared to dUMP in the wild-type enzyme. The 2.7-A crystal structure of V316Am complexed with cofactor, CH2H4folate, and the substrate analog, FdUMP, shows these ligands bound in an open conformation similar to that of the unliganded enzyme. In this ternary complex, the imidazolidine ring of the cofactor is open and has reacted with water to form 5-HOCH2H4folate. 5-HOCH2H4folate is structural evidence for the 5-iminium ion intermediate, which is the proposed reactive form of CH2H4folate. The altered ligand binding modes observed in the three V316Am complex structures open new venues for the design of novel TS inhibitors.

PubMed: 8343503
DOI: 10.1021/bi00079a007

実験手法

X-RAY DIFFRACTION (3.09 Å)