1YQ2

beta-galactosidase from Arthrobacter sp. C2-2 (isoenzyme C2-2-1)

Summary for 1YQ2

• Entry DOI: 10.2210/pdb1yq2/pdb
• Descriptor: beta-galactosidase, MAGNESIUM ION, SODIUM ION, ... (7 entities in total)
• Functional Keywords: glycosyl hydrolase family 2; tim barrel; hexamer, hydrolase
• Biological source: Arthrobacter sp. C2-2
• Total number of polymer chains: 6
• Total formula weight: 669203.28

Authors

Skalova, T.,Dohnalek, J.,Spiwok, V.,Lipovova, P.,Vondrackova, E.,Petrokova, H.,Strnad, H.,Kralova, B.,Hasek, J. (deposition date: 2005-02-01, release date: 2005-10-04, Last modification date: 2023-08-23)

Primary citation

Skalova, T.,Dohnalek, J.,Spiwok, V.,Lipovova, P.,Vondrackova, E.,Petrokova, H.,Duskova, J.,Strnad, H.,Kralova, B.,Hasek, J.
Cold-active beta-Galactosidase from Arthrobacter sp. C2-2 Forms Compact 660kDa Hexamers: Crystal Structure at 1.9A Resolution
J.Mol.Biol., 353:282-294, 2005

PubMed Abstract: The X-ray structure of cold-active beta-galactosidase (isoenzyme C-2-2-1) from an Antarctic bacterium Arthrobacter sp. C2-2 was solved at 1.9A resolution. The enzyme forms 660 kDa hexamers with active sites opened to the central cavity of the hexamer and connected by eight channels with exterior solvent. To our best knowledge, this is the first cold-active beta-galactosidase with known structure and also the first known beta-galactosidase structure in the form of compact hexamers. The hexamer organization regulates access of substrates and ligands to six active sites and this unique packing, present also in solution, raises questions about its purpose and function. This enzyme belongs to glycosyl hydrolase family 2, similarly to Escherichia coli beta-galactosidase, forming tetramers necessary for its enzymatic function. However, we discovered significant differences between these two enzymes affecting the ability of tetramer/hexamer formation and complementation of the active site. This structure reveals new insights into the cold-adaptation mechanisms of enzymatic pathways of extremophiles.

PubMed: 16171818
DOI: 10.1016/j.jmb.2005.08.028

Experimental method

X-RAY DIFFRACTION (1.9 Å)