1eg1: Difference between revisions

Revision as of 13:27, 21 February 2008

ENDOGLUCANASE I FROM TRICHODERMA REESEI

OverviewOverview

Cellulose is the most abundant polymer in the biosphere. Although generally resistant to degradation, it may be hydrolysed by cellulolytic organisms that have evolved a variety of structurally distinct enzymes, cellobiohydrolases and endoglucanases, for this purpose. Endoglucanase I (EG I) is the major endoglucanase produced by the cellulolytic fungus Trichoderma reesei, accounting for 5 to 10% of the total amount of cellulases produced by this organism. Together with EG I from Humicola insolens and T. reesei cellobiohydrolase I (CBH I), the enzyme is classified into family 7 of the glycosyl hydrolases, and it catalyses hydrolysis with a net retention of the anomeric configuration.The structure of the catalytic core domain (residues 1 to 371) of EG I from T. reesei has been determined at 3.6 A resolution by the molecular replacement method using the structures of T. reesei CBH I and H. insolens EG I as search models. By employing the 2-fold non-crystallographic symmetry (NCS), the structure was refined successfully, despite the limited resolution. The final model has an R-factor of 0.201 (Rfree 0.258).The structure of EG I reveals an extended, open substrate-binding cleft, rather than a tunnel as found in the homologous cellobiohydrolase CBH I. This confirms the earlier proposal that the tunnel-forming loops in CBH I have been deleted in EG I, which has resulted in an open active site in EG I, enabling it to function as an endoglucanase. Comparison of the structure of EG I with several related enzymes reveals structural similarities, and differences that relate to their biological function in degrading particular substrates. A possible structural explanation of the drastically different pH profiles of T. reesei and H. insolens EG I is proposed.

About this StructureAbout this Structure

1EG1 is a Single protein structure of sequence from Hypocrea jecorina with as ligand. Active as Cellulase, with EC number 3.2.1.4 Full crystallographic information is available from OCA.

ReferenceReference

The crystal structure of the catalytic core domain of endoglucanase I from Trichoderma reesei at 3.6 A resolution, and a comparison with related enzymes., Kleywegt GJ, Zou JY, Divne C, Davies GJ, Sinning I, Stahlberg J, Reinikainen T, Srisodsuk M, Teeri TT, Jones TA, J Mol Biol. 1997 Sep 26;272(3):383-97. PMID:9325098

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-[[Image:1eg1.gif|left|200px]]<br /><applet load="1eg1" size="450" color="white" frame="true" align="right" spinBox="true"
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 caption="1eg1, resolution 3.6&Aring;" />
 '''ENDOGLUCANASE I FROM TRICHODERMA REESEI'''<br />
 ==Overview==
-Cellulose is the most abundant polymer in the biosphere. Although, generally resistant to degradation, it may be hydrolysed by cellulolytic, organisms that have evolved a variety of structurally distinct enzymes, cellobiohydrolases and endoglucanases, for this purpose. Endoglucanase I, (EG I) is the major endoglucanase produced by the cellulolytic fungus, Trichoderma reesei, accounting for 5 to 10% of the total amount of, cellulases produced by this organism. Together with EG I from Humicola, insolens and T. reesei cellobiohydrolase I (CBH I), the enzyme is, classified into family 7 of the glycosyl hydrolases, and it catalyses, hydrolysis with a net retention of the anomeric configuration.The, structure of the catalytic core domain (residues 1 to 371) of EG I from T., reesei has been determined at 3.6 A resolution by the molecular, replacement method using the structures of T. reesei CBH I and H. insolens, EG I as search models. By employing the 2-fold non-crystallographic, symmetry (NCS), the structure was refined successfully, despite the, limited resolution. The final model has an R-factor of 0.201 (Rfree, 0.258).The structure of EG I reveals an extended, open substrate-binding, cleft, rather than a tunnel as found in the homologous cellobiohydrolase, CBH I. This confirms the earlier proposal that the tunnel-forming loops in, CBH I have been deleted in EG I, which has resulted in an open active site, in EG I, enabling it to function as an endoglucanase. Comparison of the, structure of EG I with several related enzymes reveals structural, similarities, and differences that relate to their biological function in, degrading particular substrates. A possible structural explanation of the, drastically different pH profiles of T. reesei and H. insolens EG I is, proposed.
+Cellulose is the most abundant polymer in the biosphere. Although generally resistant to degradation, it may be hydrolysed by cellulolytic organisms that have evolved a variety of structurally distinct enzymes, cellobiohydrolases and endoglucanases, for this purpose. Endoglucanase I (EG I) is the major endoglucanase produced by the cellulolytic fungus Trichoderma reesei, accounting for 5 to 10% of the total amount of cellulases produced by this organism. Together with EG I from Humicola insolens and T. reesei cellobiohydrolase I (CBH I), the enzyme is classified into family 7 of the glycosyl hydrolases, and it catalyses hydrolysis with a net retention of the anomeric configuration.The structure of the catalytic core domain (residues 1 to 371) of EG I from T. reesei has been determined at 3.6 A resolution by the molecular replacement method using the structures of T. reesei CBH I and H. insolens EG I as search models. By employing the 2-fold non-crystallographic symmetry (NCS), the structure was refined successfully, despite the limited resolution. The final model has an R-factor of 0.201 (Rfree 0.258).The structure of EG I reveals an extended, open substrate-binding cleft, rather than a tunnel as found in the homologous cellobiohydrolase CBH I. This confirms the earlier proposal that the tunnel-forming loops in CBH I have been deleted in EG I, which has resulted in an open active site in EG I, enabling it to function as an endoglucanase. Comparison of the structure of EG I with several related enzymes reveals structural similarities, and differences that relate to their biological function in degrading particular substrates. A possible structural explanation of the drastically different pH profiles of T. reesei and H. insolens EG I is proposed.
 ==About this Structure==
-EG1 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 NAG as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cellulase Cellulase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.4 3.2.1.4] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1EG1 OCA].
+EG1 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=NAG:'>NAG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Cellulase Cellulase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.4 3.2.1.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EG1 OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Hypocrea jecorina]]
 [[Category: Single protein]]
-[[Category: Jones, T.A.]]
+[[Category: Jones, T A.]]
-[[Category: Kleywegt, G.J.]]
+[[Category: Kleywegt, G J.]]
-[[Category: Zou, J.Y.]]
+[[Category: Zou, J Y.]]
 [[Category: NAG]]
 [[Category: cellulose degradation]]
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 [[Category: mutation]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 13:58:36 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:27:21 2008''