Glycoside Hydrolase Family 7 - Revision history

Harry Brumer: Text replacement - "\^\^\^(.*)\^\^\^" to "$1"

2021-12-18T21:15:33Z

Text replacement - "\^\^\^(.*)\^\^\^" to "$1"

Kazune Tamura: /* Three-dimensional structures */

2019-02-23T23:37:22Z

Three-dimensional structures

Harry Brumer at 16:06, 29 July 2015

2015-07-29T16:06:27Z

Harry Brumer: updated CAZyDBlink

2012-09-10T16:31:38Z

updated CAZyDBlink

Spencer Williams at 01:42, 9 June 2011

2011-06-09T01:42:42Z

Spencer Williams at 11:36, 5 July 2010

2010-07-05T11:36:44Z

Harry Brumer: /* Family Firsts */

2010-06-29T14:48:43Z

Family Firsts

Harry Brumer: /* Three-dimensional structures */

2010-06-29T14:47:27Z

Three-dimensional structures

Harry Brumer: Updated status to Curator Approved

2010-06-29T14:40:09Z

Updated status to Curator Approved

Jerry Stahlberg at 10:47, 1 March 2010

2010-03-01T10:47:25Z

@@ Line 1: / Line 1: @@
 <!-- CURATORS: Please replace the {{UnderConstruction}} tag below with {{CuratorApproved}} when the page is ready for wider public consumption -->
 {{CuratorApproved}}
-* [[Author]]: ^^^Jerry Stahlberg^^^
+* [[Author]]: [[User:Jerry Stahlberg|Jerry Stahlberg]]
-* [[Responsible Curator]]:  ^^^Jerry Stahlberg^^^
+* [[Responsible Curator]]:  [[User:Jerry Stahlberg|Jerry Stahlberg]]
 ----

@@ Line 38: / Line 38: @@
 == Three-dimensional structures ==
-Three-dimensional structures are available for both endoglucanases and cellobiohydrolases of GH7. The first cellobiohydrolase structure, the catalytic module of ''Hypocrea jecorina'' Cel7A, was published in 1994 (CBH I; [{{PDBlink}}1cel PDB 1cel]) <cite>Divne1994</cite>, and the first endoglucanase, ''Fusarium oxysporum'' EG I (Cel7B), in 1996 ([{{PDBlink}}1ovw PDB 1ovw]) <cite>Sulzenbacher1996</cite>. The proteins are built up around a &beta;-jellyroll folded framework, in which two large anti-parallell &beta;-sheets pack face-to-face to form a highly curved &beta;-sandwich. The &beta;-sandwich is further extended along both edges by several of the loops that connect the &beta;-strands, resulting in a long (~50 &Aring;) substrate-binding surface that runs perpendicular to the &beta;-strands of the inner, concave &beta;-sheet. A few short &alpha;-helical segments occur in some of the loops at the perifery of the structure. Endoglucanases have an open substrate binding cleft/groove, while in cellobiohydrolases some loops are further elongated and bend around the active site so that a more or less closed tunnel is formed through the enzyme. Further structural studies have provided detailed knowledge about catalytic mechanism and substrate binding in family 7. Some key studies include:
+Three-dimensional structures are available for both endoglucanases and cellobiohydrolases of GH7. The first cellobiohydrolase structure, the catalytic module of ''Hypocrea jecorina'' Cel7A, was published in 1994 (CBH I; [{{PDBlink}}1cel PDB 1cel]) <cite>Divne1994</cite>, and the first endoglucanase, ''Fusarium oxysporum'' EG I (Cel7B), in 1996 ([{{PDBlink}}1ovw PDB 1ovw]) <cite>Sulzenbacher1996</cite>. The proteins are built up around a &beta;-jellyroll folded framework, in which two large anti-parallel &beta;-sheets pack face-to-face to form a highly curved &beta;-sandwich. The &beta;-sandwich is further extended along both edges by several of the loops that connect the &beta;-strands, resulting in a long (~50 &Aring;) substrate-binding surface that runs perpendicular to the &beta;-strands of the inner, concave &beta;-sheet. A few short &alpha;-helical segments occur in some of the loops at the perifery of the structure. Endoglucanases have an open substrate binding cleft/groove, while in cellobiohydrolases some loops are further elongated and bend around the active site so that a more or less closed tunnel is formed through the enzyme. Further structural studies have provided detailed knowledge about catalytic mechanism and substrate binding in family 7. Some key studies include:
 * A complex of ''Fusarium oxysporum'' EG1 (Cel7B) with a non-hydrolysable substrate analog (thio-cellopentaose) indicated that transition of the glucose residue at site -1 from a <sup>4</sup><i>C</i><sub>1</sub> chair to a distorted <sup>1,4</sup><i>B</i> boat conformation is reqiured prior to hydrolysis ([{{PDBlink}}1ovw PDB 1ovw]) <cite>Sulzenbacher1996</cite>.

@@ Line 29: / Line 29: @@
 == Substrate specificities ==
-Most [[glycoside hydrolases]] of family 7 cleave &beta;-1,4 glycosidic bonds in cellulose/&beta;-1,4-glucans. Several members also show activity on xylan. The substrate specificities found in GH7 are: ''[[endo]]''-1,4-&beta;-glucanase (EC 3.2.1.4), [reducing end-acting] cellobiohydrolase (EC 3.2.1.-), chitosanase (EC 3.2.1.132) and ''[[endo]]''-1,3-1,4-&beta;-glucanase (EC 3.2.1.73).
+Most [[glycoside hydrolases]] of family 7 cleave &beta;-1,4 glycosidic bonds in cellulose/&beta;-1,4-glucans. Several members also show activity on xylan. The substrate specificities found in GH7 are: ''[[endo]]''-1,4-&beta;-glucanase (EC 3.2.1.4), [reducing end-acting] cellobiohydrolase (EC 3.2.1.-), chitosanase (EC 3.2.1.132) and ''[[endo]]''-1,3-1,4-&beta;-glucanase (EC 3.2.1.73).  GH7 was one of the first glycoside hydrolase families classified by hydrophobic cluster analysis, and was previously known as "Cellulase Family C" <cite>Henrissat1989 Gilkes1991</cite>.
 == Kinetics and Mechanism ==
@@ Line 54: / Line 54: @@
 <biblio>
 #Knowles1988 Knowles, J.K.C., Lehtovaara, P., Murray, M. and Sinnott, M.L. (1988) Stereochemical course of the action of the cellobioside hydrolases I and II of ''Trichoderma reesei''. J. Chem. Soc., Chem. Commun., 1988, 1401-1402. [http://dx.doi.org/10.1039/C39880001401 DOI: 10.1039/C39880001401]
 #Kuhls1996 pmid=8755548
 #Divne1994 pmid=8036495
 #Stahlberg1996 pmid=8951380
 #Mackenzie1998 pmid=9761741
 #Ducros2003 pmid=12890535
 #Klarskov1997 pmid=9449766
 #Sulzenbacher1997 pmid=9153432
 #Viladot1998 pmid=9698381
 #Sulzenbacher1996 pmid=8952478
 #Divne1998 pmid=9466911
 #Ubhayasekera2005 pmid=15819888
 #Parkkinen2008 pmid=18499583
+#Henrissat1989 pmid=2806912
 </biblio>
 [[Category:Glycoside Hydrolase Families|GH007]]

@@ Line 22: / Line 22: @@
 |{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
 |-
-| colspan="2" |http://www.cazy.org/fam/GH7.html
+| colspan="2" |{{CAZyDBlink}}GH7.html
 |}
 </div>

@@ Line 32: / Line 32: @@
 == Kinetics and Mechanism ==
-Family 7 enzymes are [[retaining]] enzymes, as first shown by NMR analysis <cite>Knowles1988</cite> on Cellobiohydrolase I (CBH I; Cel7A) from the fungus ''Trichoderma reesei'' (a clonal derivative of ''Hypocrea jecorina'' <cite>Kuhls1996</cite>).
+Family 7 enzymes are [[retaining]] enzymes, as first shown by NMR analysis <cite>Knowles1988</cite> on cellobiohydrolase I (CBH I; Cel7A) from the fungus ''Trichoderma reesei'' (a clonal derivative of ''Hypocrea jecorina'' <cite>Kuhls1996</cite>).
 == Catalytic Residues ==
-In GH7 enzymes the catalytic residues are positioned close to each other in sequence in the consensus motif -Glu-X-Asp-X-X-Glu-, where the first Glu acts as [[catalytic nucleophile]] and the other Glu as [[general acid/base]]. This was proposed in the first 3-D structure publication, of ''Hypocrea jecorina'' Cel7A <cite>Divne1994</cite>, based on the position of the residues relative to an ''o''-iodo-benzyl-cellobioside molecule bound at the active site. It was supported by mutational studies with the same enzyme <cite>Stahlberg1996</cite>, which also showed that the Aspartate residue in the consensus motif is important for catalysis, and with Endoglucanase I (EG I, Cel7B) from ''Humicola insolens'' <cite>Mackenzie1998 Ducros2003</cite>. The [[catalytic nucleophile]] was further supported by affinity labelling with 3,4-epoxybutyl-&beta;-cellobioside; with ''Hypocrea jecorina'' Cel7A the identification was done by ESI-MS peptide mapping and sequencing <cite>Klarskov1997</cite>, and with ''Fusarium oxysporum'' Endoglucanase I (EG I, Cel7B) the residue was identified by X-ray crystallography <cite>Sulzenbacher1997</cite>. This was subsequently verified by trapping of a 2-deoxy-2-fluorocellotriosyl covalent enzyme [[intermediate]] in ''Humicola insolens'' Cel7B and identification of the labelled peptide by tandem MS <cite>Mackenzie1998</cite>. The [[general acid/base]] has been inferred by homology to GH16, the other family in clan GH-B, where it has been verified by azide rescue of inactivated mutants of a ''Bacillus licheniformis'' 1,3-1,4-&beta;-D-glucan 4-glucanohydrolase <cite>Viladot1998</cite>.
+In GH7 enzymes the catalytic residues are positioned close to each other in sequence in the consensus motif -Glu-X-Asp-X-X-Glu-, where the first Glu acts as [[catalytic nucleophile]] and the other Glu as [[general acid/base]]. This was proposed in the first 3-D structure publication, of ''Hypocrea jecorina'' Cel7A <cite>Divne1994</cite>, based on the position of the residues relative to an ''o''-iodo-benzyl-cellobioside molecule bound at the active site. It was supported by mutational studies with the same enzyme <cite>Stahlberg1996</cite>, which also showed that the Aspartate residue in the consensus motif is important for catalysis, and with Endoglucanase I (EG I, Cel7B) from ''Humicola insolens'' <cite>Mackenzie1998 Ducros2003</cite>. The [[catalytic nucleophile]] was further supported by affinity labelling with 3,4-epoxybutyl-&beta;-cellobioside; with ''Hypocrea jecorina'' Cel7A the identification was done by ESI-MS peptide mapping and sequencing <cite>Klarskov1997</cite>, and with ''Fusarium oxysporum'' Endoglucanase I (EG I, Cel7B) the residue was identified by X-ray crystallography <cite>Sulzenbacher1997</cite>. This was subsequently verified by trapping of a 2-deoxy-2-fluorocellotriosyl covalent enzyme [[intermediate]] in ''Humicola insolens'' Cel7B and identification of the labelled peptide by tandem MS <cite>Mackenzie1998</cite>. The [[general acid/base]] has been inferred by homology to GH16, the other family in [[clan]] GH-B, where it has been verified by azide rescue of inactivated mutants of a ''Bacillus licheniformis'' 1,3-1,4-&beta;-D-glucan 4-glucanohydrolase <cite>Viladot1998</cite>.
 == Three-dimensional structures ==

@@ Line 32: / Line 32: @@
 == Kinetics and Mechanism ==
-Family 7 enzymes are [[retaining]] enzymes, as first shown by NMR <cite>Knowles1988</cite> on Cellobiohydrolase I (CBH I; Cel7A) from the fungus ''Trichoderma reesei'' (a clonal derivative of ''Hypocrea jecorina'' <cite>Kuhls1996</cite>).
+Family 7 enzymes are [[retaining]] enzymes, as first shown by NMR analysis <cite>Knowles1988</cite> on Cellobiohydrolase I (CBH I; Cel7A) from the fungus ''Trichoderma reesei'' (a clonal derivative of ''Hypocrea jecorina'' <cite>Kuhls1996</cite>).
 == Catalytic Residues ==
-In GH7 enzymes the catalytic residues are positioned close to each other in sequence in the consensus motif -Glu-X-Asp-X-X-Glu-, where the first Glu acts as [[catalytic nucleophile]] and the other Glu as [[general acid/base]]. This was proposed in the first 3-D structure publication, of ''Hypocrea jecorina'' Cel7A <cite>Divne1994</cite>, based on the position of the residues relative to a ''o''-iodo-benzyl-cellobioside molecule bound at the active site. It was supported by mutational studies with the same enzyme <cite>Stahlberg1996</cite>, which also showed that the Aspartate residue in the consensus motif is important for catalysis, and with Endoglucanase I (EG I, Cel7B) from ''Humicola insolens'' <cite>Mackenzie1998 Ducros2003</cite>. The [[catalytic nucleophile]] was further supported by affinity labelling with 3,4-epoxybutyl-&beta;-cellobioside; with ''Hypocrea jecorina'' Cel7A the identification was done by ESI-MS peptide mapping and sequencing <cite>Klarskov1997</cite>, and with ''Fusarium oxysporum'' Endoglucanase I (EG I, Cel7B) the residue was identified by X-ray crystallography <cite>Sulzenbacher1997</cite>. This was subsequently verified by trapping of a 2-deoxy-2-fluorocellotriosyl covalent enzyme intermediate in ''Humicola insolens'' Cel7B and identification of the labelled peptide by tandem MS <cite>Mackenzie1998</cite>. The [[general acid/base]] has been inferred by homology to GH16, the other family in clan GH-B, where it has been verified by azide rescue of inactivated mutants of a ''Bacillus licheniformis'' 1,3-1,4-&beta;-D-glucan 4-glucanohydrolase <cite>Viladot1998</cite>.
+In GH7 enzymes the catalytic residues are positioned close to each other in sequence in the consensus motif -Glu-X-Asp-X-X-Glu-, where the first Glu acts as [[catalytic nucleophile]] and the other Glu as [[general acid/base]]. This was proposed in the first 3-D structure publication, of ''Hypocrea jecorina'' Cel7A <cite>Divne1994</cite>, based on the position of the residues relative to an ''o''-iodo-benzyl-cellobioside molecule bound at the active site. It was supported by mutational studies with the same enzyme <cite>Stahlberg1996</cite>, which also showed that the Aspartate residue in the consensus motif is important for catalysis, and with Endoglucanase I (EG I, Cel7B) from ''Humicola insolens'' <cite>Mackenzie1998 Ducros2003</cite>. The [[catalytic nucleophile]] was further supported by affinity labelling with 3,4-epoxybutyl-&beta;-cellobioside; with ''Hypocrea jecorina'' Cel7A the identification was done by ESI-MS peptide mapping and sequencing <cite>Klarskov1997</cite>, and with ''Fusarium oxysporum'' Endoglucanase I (EG I, Cel7B) the residue was identified by X-ray crystallography <cite>Sulzenbacher1997</cite>. This was subsequently verified by trapping of a 2-deoxy-2-fluorocellotriosyl covalent enzyme [[intermediate]] in ''Humicola insolens'' Cel7B and identification of the labelled peptide by tandem MS <cite>Mackenzie1998</cite>. The [[general acid/base]] has been inferred by homology to GH16, the other family in clan GH-B, where it has been verified by azide rescue of inactivated mutants of a ''Bacillus licheniformis'' 1,3-1,4-&beta;-D-glucan 4-glucanohydrolase <cite>Viladot1998</cite>.
 == Three-dimensional structures ==
@@ Line 47: / Line 47: @@
 == Family Firsts ==
 ;First sterochemistry determination: ''Hypocrea jecorina'' cellobiohydrolase Cel7A by NMR <cite>Knowles1988</cite>.
-;First catalytic nucleophile identification: Suggested in ''Hypocrea jecorina'' cellobiohydrolase Cel7A <cite>Klarskov1997</cite> and ''Fusarium oxysporum'' endoglucanase Cel7B <cite>Sulzenbacher1997</cite> via affinity labelling with 3,4-epoxybutyl-&beta;-cellobioside. Verified in ''Humicola insolens'' Cel7B by trapping of a covalent 2-deoxy-2-fluorocellotriosyl enzyme intermediate <cite>Mackenzie1998</cite>.
+;First [[catalytic nucleophile]] identification: Suggested in ''Hypocrea jecorina'' cellobiohydrolase Cel7A <cite>Klarskov1997</cite> and ''Fusarium oxysporum'' endoglucanase Cel7B <cite>Sulzenbacher1997</cite> via affinity labelling with 3,4-epoxybutyl-&beta;-cellobioside. Verified in ''Humicola insolens'' Cel7B by trapping of a covalent 2-deoxy-2-fluorocellotriosyl enzyme [[intermediate]] <cite>Mackenzie1998</cite>.
-;First general acid/base residue identification: Suggested by structural studies and mutation in ''Hypocrea jecorina'' Cel7A <cite>Divne1994 Stahlberg1996 Divne1998</cite>. Verified in ''Bacillus licheniformis'' 1,3-1,4-&beta;-D-glucan 4-glucanohydrolase of GH16 by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
+;First [[general acid/base]] residue identification: Suggested by structural studies and mutation in ''Hypocrea jecorina'' Cel7A <cite>Divne1994 Stahlberg1996 Divne1998</cite>. Verified in ''Bacillus licheniformis'' 1,3-1,4-&beta;-D-glucan 4-glucanohydrolase of GH16 by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
 ;First 3-D structure: First cellobiohydrolase was ''Hypocrea jecorina'' Cel7A (CBH I; [{{PDBlink}}1cel PDB 1cel]) <cite>Divne1994</cite>. First ''[[endo]]''-1,4-&beta;-glucanase was Endoglucanase I (EG I; Cel7B) from ''Fusarium oxysporum'' ([{{PDBlink}}1ovw PDB 1ovw]) <cite>Sulzenbacher1996</cite>, both by X-ray crystallography.

@@ Line 38: / Line 38: @@
 == Three-dimensional structures ==
-Three-dimensional structures are available for both endoglucanases and cellobiohydrolases of GH7. The first cellobiohydrolase structure, the catalytic module of ''Hypocrea jecorina'' Cel7A, was published in 1994 (CBH I; [http://www.rcsb.org/pdb/explore/explore.do?structureId=1CEL PDB 1cel]) <cite>Divne1994</cite>, and the first endoglucanase, ''Fusarium oxysporum'' EG I (Cel7B), in 1996 ([http://www.rcsb.org/pdb/explore/explore.do?structureId=1OVW PDB 1ovw]) <cite>Sulzenbacher1996</cite>. The proteins are built up around a &beta;-jellyroll folded framework, in which two large anti-parallell &beta;-sheets pack face-to-face to form a highly curved &beta;-sandwich. The &beta;-sandwich is further extended along both edges by several of the loops that connect the &beta;-strands, resulting in a long (~50 &Aring;) substrate-binding surface that runs perpendicular to the &beta;-strands of the inner, concave &beta;-sheet. A few short &alpha;-helical segments occur in some of the loops at the perifery of the structure. Endoglucanases have an open substrate binding cleft/groove, while in cellobiohydrolases some loops are further elongated and bend around the active site so that a more or less closed tunnel is formed through the enzyme. Further structural studies have provided detailed knowledge about catalytic mechanism and substrate binding in family 7. Some key studies include:
+Three-dimensional structures are available for both endoglucanases and cellobiohydrolases of GH7. The first cellobiohydrolase structure, the catalytic module of ''Hypocrea jecorina'' Cel7A, was published in 1994 (CBH I; [{{PDBlink}}1cel PDB 1cel]) <cite>Divne1994</cite>, and the first endoglucanase, ''Fusarium oxysporum'' EG I (Cel7B), in 1996 ([{{PDBlink}}1ovw PDB 1ovw]) <cite>Sulzenbacher1996</cite>. The proteins are built up around a &beta;-jellyroll folded framework, in which two large anti-parallell &beta;-sheets pack face-to-face to form a highly curved &beta;-sandwich. The &beta;-sandwich is further extended along both edges by several of the loops that connect the &beta;-strands, resulting in a long (~50 &Aring;) substrate-binding surface that runs perpendicular to the &beta;-strands of the inner, concave &beta;-sheet. A few short &alpha;-helical segments occur in some of the loops at the perifery of the structure. Endoglucanases have an open substrate binding cleft/groove, while in cellobiohydrolases some loops are further elongated and bend around the active site so that a more or less closed tunnel is formed through the enzyme. Further structural studies have provided detailed knowledge about catalytic mechanism and substrate binding in family 7. Some key studies include:
-i) A complex of ''Fusarium oxysporum'' EG1 (Cel7B) with a non-hydrolysable substrate analog (thio-cellopentaose) indicated that transition of the glucose residue at site -1 from a <sup>4</sup><i>C</i><sub>1</sub> chair to a distorted <sup>1,4</sup><i>B</i> boat conformation is reqiured prior to hydrolysis ([http://www.rcsb.org/pdb/explore/explore.do?structureId=1OVW PDB 1ovw]) <cite>Sulzenbacher1996</cite>.
+* A complex of ''Fusarium oxysporum'' EG1 (Cel7B) with a non-hydrolysable substrate analog (thio-cellopentaose) indicated that transition of the glucose residue at site -1 from a <sup>4</sup><i>C</i><sub>1</sub> chair to a distorted <sup>1,4</sup><i>B</i> boat conformation is reqiured prior to hydrolysis ([{{PDBlink}}1ovw PDB 1ovw]) <cite>Sulzenbacher1996</cite>.
+* Cellooligosaccharides bound in catalytically deficient mutants of ''Hypocrea jecorina'' Cel7A revealed 10 discrete glucosyl-binding subsites, -7 to +3, and allowed modelling of a productively bound cellulose chain along the entire tunnel of the enzyme <cite>Stahlberg1996 Divne1998</cite>.
-ii) Cellooligosaccharides bound in catalytically deficient mutants of ''Hypocrea jecorina'' Cel7A revealed 10 discrete glucosyl-binding subsites, -7 to +3, and allowed modelling of a productively bound cellulose chain along the entire tunnel of the enzyme <cite>Stahlberg1996 Divne1998</cite>.
+* The discovery of two discrete binding modes for cellobiose in the product sites +1/+2 in ''Hypocrea jecorina'' Cel7A and ''Phanerochaete chrysosporium'' Cel7D, indicated that hydrolysis of the glycosyl-enzyme intermediate may proceed without prior release of the cellobiose product, and suggests a product ejection mechanism during processive hydrolysis of cellulose <cite>Ubhayasekera2005</cite>.
+* Later studies of oligosaccharide binding in ''Melanocarpus albomyces'' Cel7B provide further insight into the flexibility of sugar binding within the tunnel of a cellobiohydrolase <cite>Parkkinen2008</cite>.
 == Family Firsts ==

@@ Line 52: / Line 52: @@
 ;First catalytic nucleophile identification: Suggested in ''Hypocrea jecorina'' cellobiohydrolase Cel7A <cite>Klarskov1997</cite> and ''Fusarium oxysporum'' endoglucanase Cel7B <cite>Sulzenbacher1997</cite> via affinity labelling with 3,4-epoxybutyl-&beta;-cellobioside. Verified in ''Humicola insolens'' Cel7B by trapping of a covalent 2-deoxy-2-fluorocellotriosyl enzyme intermediate <cite>Mackenzie1998</cite>.
 ;First general acid/base residue identification: Suggested by structural studies and mutation in ''Hypocrea jecorina'' Cel7A <cite>Divne1994 Stahlberg1996 Divne1998</cite>. Verified in ''Bacillus licheniformis'' 1,3-1,4-&beta;-D-glucan 4-glucanohydrolase of GH16 by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
-;First 3-D structure: First cellobiohydrolase was ''Hypocrea jecorina'' Cel7A (CBH I; [http://www.rcsb.org/pdb/explore/explore.do?structureId=1CEL PDB 1cel]) <cite>Divne1994</cite>. First ''[[endo]]''-1,4-&beta;-glucanase was Endoglucanase I (EG I, Cel7B) from ''Fusarium oxysporum'' ([http://www.rcsb.org/pdb/explore/explore.do?structureId=1OVW PDB 1ovw]) <cite>Sulzenbacher1996</cite>, both by X-ray crystallography.
+;First 3-D structure: First cellobiohydrolase was ''Hypocrea jecorina'' Cel7A (CBH I; [http://www.rcsb.org/pdb/explore/explore.do?structureId=1CEL PDB 1cel]) <cite>Divne1994</cite>. First ''[[endo]]''-1,4-&beta;-glucanase was Endoglucanase I (EG I; Cel7B) from ''Fusarium oxysporum'' ([http://www.rcsb.org/pdb/explore/explore.do?structureId=1OVW PDB 1ovw]) <cite>Sulzenbacher1996</cite>, both by X-ray crystallography.
 == References ==