6PK1

Alanine-glyoxylate aminotransferase 1 (AGT1) from Arabidopsis thaliana in presence of serine

6PK1 の概要

• エントリーDOI: 10.2210/pdb6pk1/pdb
• 関連するPDBエントリー: 6PK3
• 分子名称: Serine--glyoxylate aminotransferase, PYRIDOXAL-5'-PHOSPHATE, 3-HYDROXYPYRUVIC ACID, ... (4 entities in total)
• 機能のキーワード: photorespiration, serine-glyoxylate aminotransferase, plp, peroxisomal enzyme, transferase
• 由来する生物種: Arabidopsis thaliana (Mouse-ear cress)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 89112.10

構造登録者

Liepman, A.H.,Saper, M.A. (登録日: 2019-06-28, 公開日: 2019-10-23, 最終更新日: 2023-10-11)

主引用文献

Liepman, A.H.,Vijayalakshmi, J.,Peisach, D.,Hulsebus, B.,Olsen, L.J.,Saper, M.A.
Crystal Structure Of Photorespiratory Alanine:Glyoxylate Aminotransferase 1 (AGT1) FromArabidopsis thaliana.
Front Plant Sci, 10:1229-1229, 2019

PubMed Abstract: Photorespiration is an energetically costly metabolic pathway for the recycling of phosphoglycolate produced by the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) to phosphoglycerate. alanine:glyoxylate aminotransferase 1 (AGT1) is a peroxisomal aminotransferase with a central role in photorespiration. This enzyme catalyzes various aminotransferase reactions, including serine:glyoxylate, alanine:glyoxylate, and asparagine:glyoxylate transaminations. To better understand structural features that govern the specificity of this enzyme, its crystal structures in the native form (2.2-Å resolution) and in the presence of l-serine (2.1-Å resolution) were solved. The structures confirm that this enzyme is dimeric, in agreement with studies of the active enzyme in solution. In the crystal, another dimer related by noncrystallographic symmetry makes close interactions to form a tetramer mediated in part by an extra carboxyl-terminal helix conserved in plant homologs of AGT1. Pyridoxal 5'-phosphate (PLP) is bound at the active site but is not held in place by covalent interactions. Residues Tyr35' and Arg36', entering the active site from the other subunits in the dimer, mediate interactions between AGT and l-serine when used as a substrate. In comparison, AGT1 from humans and AGT1 from lack these two residues and instead position a tyrosine ring into the binding site, which accounts for their preference for l-alanine instead of l-serine. The structure also rationalizes the phenotype of the mutant, Pro251 to Leu, which likely affects the dimer interface near the catalytic site. This structural model of AGT1 provides valuable new information about this protein that may enable improvements to the efficiency of photorespiration.

PubMed: 31681359
DOI: 10.3389/fpls.2019.01229

実験手法

X-RAY DIFFRACTION (2.1 Å)