1zm1
|
Crystal structures of complex F. succinogenes 1,3-1,4-beta-D-glucanase and beta-1,3-1,4-cellotriose
OverviewOverview
Fibrobacter succinogenes 1,3-1,4-beta-D-glucanase (Fsbeta-glucanase) catalyzes the specific hydrolysis of beta-1,4 glycosidic bonds adjacent to beta-1,3 linkages in beta-D-glucans or lichenan. This is the first report to elucidate the crystal structure of a truncated Fsbeta-glucanase (TFsbeta-glucanase) in complex with beta-1,3-1,4-cellotriose, a major product of the enzyme reaction. The crystal structures, at a resolution of 2.3 angstroms, reveal that the overall fold of TFsbeta-glucanase remains virtually unchanged upon sugar binding. The enzyme accommodates five glucose residues, forming a concave active cleft. The beta-1,3-1,4-cellotriose with subsites -3 to -1 bound to the active cleft of TFsbeta-glucanase with its reducing end subsite -1 close to the key catalytic residues Glu56 and Glu60. All three subsites of the beta-1,3-1,4-cellotriose adopted a relaxed C(1)4 conformation, with a beta-1,3 glycosidic linkage between subsites -2 and -1, and a beta-1,4 glycosidic linkage between subsites -3 and -2. On the basis of the enzyme-product complex structure observed in this study, a catalytic mechanism and substrate binding conformation of the active site of TFsbeta-glucanase is proposed.
About this StructureAbout this Structure
1ZM1 is a Single protein structure of sequence from Fibrobacter succinogenes with as ligand. Active as Licheninase, with EC number 3.2.1.73 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of truncated Fibrobacter succinogenes 1,3-1,4-beta-D-glucanase in complex with beta-1,3-1,4-cellotriose., Tsai LC, Shyur LF, Cheng YS, Lee SH, J Mol Biol. 2005 Dec 2;354(3):642-51. Epub 2005 Sep 30. PMID:16246371
Page seeded by OCA on Thu Feb 21 16:16:59 2008