1qw8: Difference between revisions

Revision as of 15:44, 21 February 2008

Crystal structure of a family 51 alpha-L-arabinofuranosidase in complex with Ara-alpha(1,3)-Xyl

OverviewOverview

High-resolution crystal structures of alpha-L-arabinofuranosidase from Geobacillus stearothermophilus T-6, a family 51 glycosidase, are described. The enzyme is a hexamer, and each monomer is organized into two domains: a (beta/alpha)8-barrel and a 12-stranded beta sandwich with jelly-roll topology. The structures of the Michaelis complexes with natural and synthetic substrates, and of the transient covalent arabinofuranosyl-enzyme intermediate represent two stable states in the double displacement mechanism, and allow thorough examination of the catalytic mechanism. The arabinofuranose sugar is tightly bound and distorted by an extensive network of hydrogen bonds. The two catalytic residues are 4.7 A apart, and together with other conserved residues contribute to the stabilization of the oxocarbenium ion-like transition state via charge delocalization and specific protein-substrate interactions. The enzyme is an anti-protonator, and a 1.7 A electrophilic migration of the anomeric carbon takes place during the hydrolysis.

About this StructureAbout this Structure

1QW8 is a Single protein structure of sequence from Geobacillus stearothermophilus with as ligand. Active as Alpha-N-arabinofuranosidase, with EC number 3.2.1.55 Full crystallographic information is available from OCA.

ReferenceReference

Crystal structure and snapshots along the reaction pathway of a family 51 alpha-L-arabinofuranosidase., Hovel K, Shallom D, Niefind K, Belakhov V, Shoham G, Baasov T, Shoham Y, Schomburg D, EMBO J. 2003 Oct 1;22(19):4922-32. PMID:14517232

Page seeded by OCA on Thu Feb 21 14:44:19 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

@@ Line 1: / Line 1: @@
-[[Image:1qw8.jpg|left|200px]]<br /><applet load="1qw8" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1qw8.jpg|left|200px]]<br /><applet load="1qw8" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1qw8, resolution 1.80&Aring;" />
 '''Crystal structure of a family 51 alpha-L-arabinofuranosidase in complex with Ara-alpha(1,3)-Xyl'''<br />
 ==Overview==
-High-resolution crystal structures of alpha-L-arabinofuranosidase from, Geobacillus stearothermophilus T-6, a family 51 glycosidase, are, described. The enzyme is a hexamer, and each monomer is organized into two, domains: a (beta/alpha)8-barrel and a 12-stranded beta sandwich with, jelly-roll topology. The structures of the Michaelis complexes with, natural and synthetic substrates, and of the transient covalent, arabinofuranosyl-enzyme intermediate represent two stable states in the, double displacement mechanism, and allow thorough examination of the, catalytic mechanism. The arabinofuranose sugar is tightly bound and, distorted by an extensive network of hydrogen bonds. The two catalytic, residues are 4.7 A apart, and together with other conserved residues, contribute to the stabilization of the oxocarbenium ion-like transition, state via charge delocalization and specific protein-substrate, interactions. The enzyme is an anti-protonator, and a 1.7 A electrophilic, migration of the anomeric carbon takes place during the hydrolysis.
+High-resolution crystal structures of alpha-L-arabinofuranosidase from Geobacillus stearothermophilus T-6, a family 51 glycosidase, are described. The enzyme is a hexamer, and each monomer is organized into two domains: a (beta/alpha)8-barrel and a 12-stranded beta sandwich with jelly-roll topology. The structures of the Michaelis complexes with natural and synthetic substrates, and of the transient covalent arabinofuranosyl-enzyme intermediate represent two stable states in the double displacement mechanism, and allow thorough examination of the catalytic mechanism. The arabinofuranose sugar is tightly bound and distorted by an extensive network of hydrogen bonds. The two catalytic residues are 4.7 A apart, and together with other conserved residues contribute to the stabilization of the oxocarbenium ion-like transition state via charge delocalization and specific protein-substrate interactions. The enzyme is an anti-protonator, and a 1.7 A electrophilic migration of the anomeric carbon takes place during the hydrolysis.
 ==About this Structure==
-QW8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Geobacillus_stearothermophilus Geobacillus stearothermophilus] with KHO as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Alpha-N-arabinofuranosidase Alpha-N-arabinofuranosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.55 3.2.1.55] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1QW8 OCA].
+QW8 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Geobacillus_stearothermophilus Geobacillus stearothermophilus] with <scene name='pdbligand=KHO:'>KHO</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Alpha-N-arabinofuranosidase Alpha-N-arabinofuranosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.55 3.2.1.55] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QW8 OCA].
 ==Reference==
@@ Line 25: / Line 25: @@
 [[Category: hydrolase]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 01:03:24 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:44:19 2008''