Repozytorium publikacji - Politechnika Gdańska

A psychrotrophic bacterium producing a coldadaptedB-galactosidase upon growth at low temperatureswas classiWed as Arthrobacter sp. 20B. A genomic DNAlibrary of strain 20B introduced into Escherichia coliTOP10F' and screening on X-Gal (5-bromo-4-chloro-3-indolyl-B-D-galactopyranoside)-containing agar plates ledto the isolation of B-galactosidase gene. The B-galactosidasegene (bgaS) encoding a protein of 1,053 amino acids,with a calculated molecular mass of 113,695 kDa. Analysisof the amino acid sequence of BgaS protein, deduced fromthe bgaS ORF, suggested that it is a member of the glycosylhydrolase family 2. A native cold-adapted B-galactosidasewas puriWed to homogeneity and characterized. It is ahomotetrameric enzyme, each subunit being approximately116 kDa polypeptide as deduced from native and SDS-PAGE, respectively. The B-galactosidase was optimallyactive at pH 6.0-8.0 and 25°C. P-nitrophenyl-B-D-galactopyranoside(PNPG) is its preferred substrate (three timeshigher activity than for ONPG-o-nitrophenyl-B-D-galactopyranoside).The Arthrobacter sp. 20B Beta-galactosidase isactivated by thiol compounds (53% rise in activity in thepresence of 10 mM 2-mercaptoethanol), some metal ions(activity increased by 50% for Na+, K+ and by 11% forMn2+) and inactivated by pCMB (4-chloro-mercuribenzoicacid) and heavy metal ions (Pb2+, Zn2+, Cu2+).

Autorzy

• Aneta Białkowska,
• dr hab. inż. Hubert Cieśliński link otwiera się w nowej karcie ,
• Karolina Nowakowska,
• prof. dr hab. Józef Kur link otwiera się w nowej karcie ,
• Marianna Turkiewicz