1bcx: Difference between revisions

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MUTATIONAL AND CRYSTALLOGRAPHIC ANALYSES OF THE ACTIVE SITE RESIDUES OF THE BACILLUS CIRCULANS XYLANASE

OverviewOverview

Using site-directed mutagenesis we have investigated the catalytic residues in a xylanase from Bacillus circulans. Analysis of the mutants E78D and E172D indicated that mutations in these conserved residues do not grossly alter the structure of the enzyme and that these residues participate in the catalytic mechanism. We have now determined the crystal structure of an enzyme-substrate complex to 108 A resolution using a catalytically incompetent mutant (E172C). In addition to the catalytic residues, Glu 78 and Glu 172, we have identified 2 tyrosine residues, Tyr 69 and Tyr 80, which likely function in substrate binding, and an arginine residue, Arg 112, which plays an important role in the active site of this enzyme. On the basis of our work we would propose that Glu 78 is the nucleophile and that Glu 172 is the acid-base catalyst in the reaction.

About this StructureAbout this Structure

1BCX is a Single protein structure of sequence from Bacillus circulans 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

Mutational and crystallographic analyses of the active site residues of the Bacillus circulans xylanase., Wakarchuk WW, Campbell RL, Sung WL, Davoodi J, Yaguchi M, Protein Sci. 1994 Mar;3(3):467-75. PMID:8019418

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-[[Image:1bcx.jpg|left|200px]]<br /><applet load="1bcx" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1bcx.jpg|left|200px]]<br /><applet load="1bcx" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1bcx, resolution 1.81&Aring;" />
 '''MUTATIONAL AND CRYSTALLOGRAPHIC ANALYSES OF THE ACTIVE SITE RESIDUES OF THE BACILLUS CIRCULANS XYLANASE'''<br />
 ==Overview==
-Using site-directed mutagenesis we have investigated the catalytic, residues in a xylanase from Bacillus circulans. Analysis of the mutants, E78D and E172D indicated that mutations in these conserved residues do not, grossly alter the structure of the enzyme and that these residues, participate in the catalytic mechanism. We have now determined the crystal, structure of an enzyme-substrate complex to 108 A resolution using a, catalytically incompetent mutant (E172C). In addition to the catalytic, residues, Glu 78 and Glu 172, we have identified 2 tyrosine residues, Tyr, 69 and Tyr 80, which likely function in substrate binding, and an arginine, residue, Arg 112, which plays an important role in the active site of this, enzyme. On the basis of our work we would propose that Glu 78 is the, nucleophile and that Glu 172 is the acid-base catalyst in the reaction.
+Using site-directed mutagenesis we have investigated the catalytic residues in a xylanase from Bacillus circulans. Analysis of the mutants E78D and E172D indicated that mutations in these conserved residues do not grossly alter the structure of the enzyme and that these residues participate in the catalytic mechanism. We have now determined the crystal structure of an enzyme-substrate complex to 108 A resolution using a catalytically incompetent mutant (E172C). In addition to the catalytic residues, Glu 78 and Glu 172, we have identified 2 tyrosine residues, Tyr 69 and Tyr 80, which likely function in substrate binding, and an arginine residue, Arg 112, which plays an important role in the active site of this enzyme. On the basis of our work we would propose that Glu 78 is the nucleophile and that Glu 172 is the acid-base catalyst in the reaction.
 ==About this Structure==
-BCX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_circulans Bacillus circulans] with SO4 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=1BCX OCA].
+BCX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_circulans Bacillus circulans] with <scene name='pdbligand=SO4:'>SO4</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=1BCX OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Endo-1,4-beta-xylanase]]
 [[Category: Single protein]]
-[[Category: Campbell, R.L.]]
+[[Category: Campbell, R L.]]
-[[Category: Wakarchuk, W.W.]]
+[[Category: Wakarchuk, W W.]]
 [[Category: SO4]]
 [[Category: hydrolase(xylan degradation)]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 11:33:11 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:53:57 2008''