1yq2
From Proteopedia
beta-galactosidase from Arthrobacter sp. C2-2 (isoenzyme C2-2-1)
Overview
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.
About this Structure
1YQ2 is a Single protein structure of sequence from Bacteria. Full crystallographic information is available from OCA.
Reference
Cold-active beta-galactosidase from Arthrobacter sp. C2-2 forms compact 660 kDa hexamers: crystal structure at 1.9A resolution., Skalova T, Dohnalek J, Spiwok V, Lipovova P, Vondrackova E, Petrokova H, Duskova J, Strnad H, Kralova B, Hasek J, J Mol Biol. 2005 Oct 21;353(2):282-94. PMID:16171818 Page seeded by OCA on Sat May 3 16:38:04 2008
