1xyn: Difference between revisions

Revision as of 17:00, 21 February 2008

STRUCTURAL COMPARISON OF TWO MAJOR ENDO-1,4-BETA-XYLANASES FROM TRICHODREMA REESEI

OverviewOverview

Three-dimensional structures of two major endo-1,4-xylanases, XYNI and XYNII from Trichoderma reesei, have been determined by X-ray crystallography. The amino acid sequences of both enzymes are highly homologous (identity approximately 50%), and both XYNI and XYNII exist as a single domain that contains two mostly antiparallel beta-sheets which are packed against each other. The beta-sheet structure is twisted, forming a cleft where the active site is situated. Two glutamic acids in the cleft, Glu75 and Glu164 in XYNI as well as Glu86 and Glu177 in XYNII, are most likely involved in catalysis. Inspection of the structures reveals that the width of the active site cleft and the number of subsites are different in XYNI and XYNII. The active site is narrower in XYNI and probably contains only three subsites, whereas the number of subsites in XYNII is most likely five. Variations in the surroundings of catalytic residue Glu164XYNI/Glu177XYNII are thought to explain the pH optimum differences observed in XYNI and XYNII.

About this StructureAbout this Structure

1XYN is a Single protein structure of sequence from Hypocrea jecorina with as ligand. Active as Endo-1,4-beta-xylanase, with EC number 3.2.1.8 Full crystallographic information is available from OCA.

ReferenceReference

Structural comparison of two major endo-1,4-xylanases from Trichoderma reesei., Torronen A, Rouvinen J, Biochemistry. 1995 Jan 24;34(3):847-56. PMID:7827044

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 '''STRUCTURAL COMPARISON OF TWO MAJOR ENDO-1,4-BETA-XYLANASES FROM TRICHODREMA REESEI'''<br />
 ==Overview==
-Three-dimensional structures of two major endo-1,4-xylanases, XYNI and, XYNII from Trichoderma reesei, have been determined by X-ray, crystallography. The amino acid sequences of both enzymes are highly, homologous (identity approximately 50%), and both XYNI and XYNII exist as, a single domain that contains two mostly antiparallel beta-sheets which, are packed against each other. The beta-sheet structure is twisted, forming a cleft where the active site is situated. Two glutamic acids in, the cleft, Glu75 and Glu164 in XYNI as well as Glu86 and Glu177 in XYNII, are most likely involved in catalysis. Inspection of the structures, reveals that the width of the active site cleft and the number of subsites, are different in XYNI and XYNII. The active site is narrower in XYNI and, probably contains only three subsites, whereas the number of subsites in, XYNII is most likely five. Variations in the surroundings of catalytic, residue Glu164XYNI/Glu177XYNII are thought to explain the pH optimum, differences observed in XYNI and XYNII.
+Three-dimensional structures of two major endo-1,4-xylanases, XYNI and XYNII from Trichoderma reesei, have been determined by X-ray crystallography. The amino acid sequences of both enzymes are highly homologous (identity approximately 50%), and both XYNI and XYNII exist as a single domain that contains two mostly antiparallel beta-sheets which are packed against each other. The beta-sheet structure is twisted, forming a cleft where the active site is situated. Two glutamic acids in the cleft, Glu75 and Glu164 in XYNI as well as Glu86 and Glu177 in XYNII, are most likely involved in catalysis. Inspection of the structures reveals that the width of the active site cleft and the number of subsites are different in XYNI and XYNII. The active site is narrower in XYNI and probably contains only three subsites, whereas the number of subsites in XYNII is most likely five. Variations in the surroundings of catalytic residue Glu164XYNI/Glu177XYNII are thought to explain the pH optimum differences observed in XYNI and XYNII.
 ==About this Structure==
-XYN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Hypocrea_jecorina Hypocrea jecorina] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Endo-1,4-beta-xylanase Endo-1,4-beta-xylanase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.8 3.2.1.8] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1XYN OCA].
+XYN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Hypocrea_jecorina Hypocrea jecorina] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Endo-1,4-beta-xylanase Endo-1,4-beta-xylanase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.8 3.2.1.8] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XYN OCA].
 ==Reference==
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 [[Category: xylanase]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 06:26:25 2007''
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