Gentisate 1,2-dioxygenase from Haloferax sp. D1227

Area of Science:

• Biochemistry
• Extremophile Research
• Enzymology

Background:

• Gentisate 1,2-dioxygenase enzymes are crucial for aromatic compound degradation.
• Extreme halophiles, like Haloferax sp. D1227, possess unique enzymes adapted to high salt environments.

Purpose of the Study:

• To purify and characterize gentisate 1,2-dioxygenase from the extreme halophile Haloferax sp. D1227.
• To investigate the enzyme's properties, optimal activity conditions, and genetic basis.

Main Methods:

• Purification using a three-step procedure.
• Determination of subunit and native molecular weights.
• Cloning, sequencing, and expression of the encoding gene.
• Bioinformatic analysis of the deduced amino acid sequence.

Main Results:

• The enzyme is a homotetramer with subunits of 42 kDa and a native molecular weight of 174 kDa.
• Optimal activity was observed at 2 M salt (KCl or NaCl), 45°C, and pH 7.2.
• The amino acid sequence analysis revealed characteristics typical of halophilic enzymes, including novel histidine clusters.

Conclusions:

• Gentisate 1,2-dioxygenase from Haloferax sp. D1227 is a stable, halophilic enzyme with specific activity optima.
• The genetic and sequence data provide insights into the adaptation of enzymes to extreme environments.