5CGZ

Crystal structure of GalB, the 4-carboxy-2-hydroxymuconate hydratase, from Pseuodomonas putida KT2440

5CGZ の概要

• エントリーDOI: 10.2210/pdb5cgz/pdb
• 分子名称: 4-oxalmesaconate hydratase, ZINC ION, GLYCEROL, ... (4 entities in total)
• 機能のキーワード: galb, hydratase, metalloenzyme, rossmann fold, helical hairpin, gallic acid, hexamer, lyase
• 由来する生物種: Pseudomonas putida (strain KT2440)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 55717.81

構造登録者

Mazurkewich, S.,Brott, A.S.,Kimber, M.S.,Seah, S.Y.K. (登録日: 2015-07-09, 公開日: 2016-02-17, 最終更新日: 2024-03-06)

主引用文献

Mazurkewich, S.,Brott, A.S.,Kimber, M.S.,Seah, S.Y.
Structural and Kinetic Characterization of the 4-Carboxy-2-hydroxymuconate Hydratase from the Gallate and Protocatechuate 4,5-Cleavage Pathways of Pseudomonas putida KT2440.
J.Biol.Chem., 291:7669-7686, 2016

PubMed Abstract: The bacterial catabolism of lignin and its breakdown products is of interest for applications in industrial processing of ligno-biomass. The gallate degradation pathway ofPseudomonas putidaKT2440 requires a 4-carboxy-2-hydroxymuconate (CHM) hydratase (GalB), which has a 12% sequence identity to a previously identified CHM hydratase (LigJ) fromSphingomonassp. SYK-6. The structure of GalB was determined and found to be a member of the PIG-LN-acetylglucosamine deacetylase family; GalB is structurally distinct from the amidohydrolase fold of LigJ. LigJ has the same stereospecificity as GalB, providing an example of convergent evolution for catalytic conversion of a common metabolite in bacterial aromatic degradation pathways. Purified GalB contains a bound Zn(2+)cofactor; however the enzyme is capable of using Fe(2+)and Co(2+)with similar efficiency. The general base aspartate in the PIG-L deacetylases is an alanine in GalB; replacement of the alanine with aspartate decreased the GalB catalytic efficiency for CHM by 9.5 × 10(4)-fold, and the variant enzyme did not have any detectable hydrolase activity. Kinetic analyses and pH dependence studies of the wild type and variant enzymes suggested roles for Glu-48 and His-164 in the catalytic mechanism. A comparison with the PIG-L deacetylases led to a proposed mechanism for GalB wherein Glu-48 positions and activates the metal-ligated water for the hydration reaction and His-164 acts as a catalytic acid.

PubMed: 26867578
DOI: 10.1074/jbc.M115.682054

実験手法

X-RAY DIFFRACTION (2.103 Å)