1QZ9

The Three Dimensional Structure of Kynureninase from Pseudomonas fluorescens

1QZ9 の概要

• エントリーDOI: 10.2210/pdb1qz9/pdb
• 分子名称: KYNURENINASE, CHLORIDE ION, PYRIDOXAL-5'-PHOSPHATE, ... (5 entities in total)
• 機能のキーワード: kynurenine, tryptophan, plp, vitamin b6, pyridoxal-5'-phosphate, hydrolase
• 由来する生物種: Pseudomonas fluorescens
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 46482.90

構造登録者

Momany, C.,Levdikov, V.,Blagova, L.,Lima, S.,Phillips, R.S. (登録日: 2003-09-16, 公開日: 2004-01-20, 最終更新日: 2023-08-23)

主引用文献

Momany, C.,Levdikov, V.,Blagova, L.,Lima, S.,Phillips, R.S.
Three-Dimensional Structure of Kynureninase from Pseudomonas fluorescens.
Biochemistry, 43:1193-1203, 2004

PubMed Abstract: Kynureninase [E.C. 3.7.1.3] is a pyridoxal-5'-phosphate (PLP)-dependent enzyme that catalyzes the hydrolytic cleavage of l-kynurenine to anthranilic acid and l-alanine. Sequence alignment with other PLP-dependent enzymes indicated that kynureninase is in subgroup IVa of the aminotransferases, along with nifS, CsdB, and serine-pyruvate aminotransferase, which suggests that kynureninase has an aminotransferase fold. Crystals of Pseudomonas fluorescens kynureninase were obtained, and the structure was solved by molecular replacement using the CsdB coordinates combined with multiple isomorphous heavy atom replacement. The coordinates were deposited in the PDB (ID code 1QZ9). The structure, refined to an R factor of 15.5% to 1.85 A resolution, is dimeric and has the aminotransferase fold. The structure also confirms the prediction from sequence alignment that Lys-227 is the PLP-binding residue in P. fluorescens kynureninase. The conserved Asp-201, expected for an aminotransferase fold, is located near the PLP nitrogen, but Asp-132 is also strictly conserved and at a similar distance from the pyridinium nitrogen. Mutagenesis of both conserved aspartic acids shows that both contribute equally to PLP binding, but Asp-201 has a greater role in catalysis. The structure shows that Tyr-226 donates a hydrogen bond to the phosphate of PLP. Unusual among PLP-dependent enzymes, Trp-256, which is also strictly conserved in kynureninases from bacteria to humans, donates a hydrogen bond to the phosphate through the indole N1-hydrogen.

PubMed: 14756555
DOI: 10.1021/bi035744e

実験手法

X-RAY DIFFRACTION (1.85 Å)