5YB0

Crystal Structure of Wild Type Phosphoserine aminotransferase (PSAT) from E. histolytica

5YB0 の概要

• エントリーDOI: 10.2210/pdb5yb0/pdb
• 分子名称: Phosphoserine aminotransferase, PYRIDOXAL-5'-PHOSPHATE, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: phosphoserine aminotransferase, transferase
• 由来する生物種: Entamoeba histolytica
• タンパク質・核酸の鎖数: 12
• 化学式量合計: 489668.26

構造登録者

Singh, R.K.,Gourinath, S. (登録日: 2017-09-02, 公開日: 2018-10-31, 最終更新日: 2024-05-08)

主引用文献

Singh, R.K.,Tomar, P.,Dharavath, S.,Kumar, S.,Gourinath, S.
N-terminal residues are crucial for quaternary structure and active site conformation for the phosphoserine aminotransferase from enteric human parasite E. histolytica.
Int.J.Biol.Macromol., 132:1012-1023, 2019

PubMed Abstract: Phosphoserine aminotransferase (PSAT) is a pyridoxal-5'phosphate (PLP)-dependent enzyme that catalyzes the second reversible step in the phosphoserine biosynthetic pathway producing serine. The crystal structure of E. histolytica PSAT (EhPSAT) complexed with PLP was elucidated at 3.0 Å resolution and the structures of its mutants, EhPSAT_Δ45 and EhPSAT_Δ4, at 1.8 and 2.4 Å resolution respectively. Deletion of 45 N-terminal residues (EhPSAT_Δ45) resulted in an inactive protein, the structure showed a dimeric arrangement drastically different from that of the wild-type protein, with the two monomers translated and rotated by almost 180° with respect to each other; causing a rearrangement of the active site to which PLP was unable to bind. Deletion of first N-terminal 15 (EhPSAT_Δ15) and four 11th to 14th residues (EhPSAT_Δ4) yielded up to 98% and 90% decrease in the activity respectively. Absence of aldimine linkage between PLP-Lys in the crystal structure of EhPSAT_Δ4 mutant explains for such decrease in activity and describes the importance of these N-terminal residues. Furthermore, a halide-binding site was found in close proximity to the active site. A stretch of six amino acids (146-NNTIYG-151) only conserved in the Entamoeba genus, contributes to halide binding may explain that the halide inhibition could be specific to Entamoeba.

PubMed: 30959130
DOI: 10.1016/j.ijbiomac.2019.04.027

実験手法

X-RAY DIFFRACTION (2.94 Å)