7ERV

Crystal structure of L-histidine decarboxylase (C57S/C101V/C282V mutant) from Photobacterium phosphoreum

7ERV の概要

• エントリーDOI: 10.2210/pdb7erv/pdb
• 分子名称: Histidine decarboxylase, IMIDAZOLE (3 entities in total)
• 機能のキーワード: lyase, decarboxylase
• 由来する生物種: Photobacterium phosphoreum
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 42365.71

構造登録者

Oda, Y.,Nakata, K.,Yamaguchi, H.,Kashiwagi, T.,Miyano, H.,Mizukoshi, T. (登録日: 2021-05-07, 公開日: 2022-02-16, 最終更新日: 2023-11-29)

主引用文献

Oda, Y.,Nakata, K.,Miyano, H.,Mizukoshi, T.,Yamaguchi, H.,Kashiwagi, T.
Structural insights into the enhanced thermostability of cysteine substitution mutants of L-histidine decarboxylase from Photobacterium phosphoreum.
J.Biochem., 171:31-40, 2022

PubMed Abstract: Enzymatic amino acid assays are important in physiological research and clinical diagnostics because abnormal amino acid concentrations in biofluids are associated with various diseases. L-histidine decarboxylase from Photobacterium phosphoreum (PpHDC) is a pyridoxal 5'-phosphate-dependent enzyme and a candidate for use in an L-histidine quantitation assay. Previous cysteine substitution experiments demonstrated that the PpHDC C57S mutant displayed improved long-term storage stability and thermostability when compared with those of the wild-type enzyme. In this study, combinational mutation experiments of single cysteine substitution mutants of PpHDC were performed, revealing that the PpHDC C57S/C101V/C282V mutant possessed the highest thermostability. The stabilizing mechanism of these mutations was elucidated by solving the structures of PpHDC C57S and C57S/C101V/C282V mutants by X-ray crystallography. In the crystal structures, two symmetry-related PpHDC molecules form a domain-swapped homodimer. The side chain of S57 is solvent exposed in the structure, indicating that the C57S mutation eliminates chemical oxidation or disulfide bond formation with a free thiol group, thereby providing greater stability. Residues 101 and 282 form hydrophobic interactions with neighboring hydrophobic residues. Mutations C101V and C282V enhanced thermostability of PpHDC by filling a cavity present in the hydrophobic core (C101V) and increasing hydrophobic interactions.

PubMed: 34622278
DOI: 10.1093/jb/mvab103

実験手法

X-RAY DIFFRACTION (2.5 Å)