Carbohydrate Binding Module Family 78 - Revision history

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

2021-12-18T21:18:35Z

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

Harry Brumer: /* Ligand specificities */ Added intrawiki link to CBM types in Lexicon

2018-02-28T16:14:58Z

Ligand specificities: Added intrawiki link to CBM types in Lexicon

Elizabeth Ficko-Blean at 08:25, 27 February 2018

2018-02-27T08:25:27Z

Harry Brumer: /* Ligand specificities */

2018-02-27T01:58:33Z

Ligand specificities

Harry Brumer: /* Ligand specificities */

2018-02-27T01:58:04Z

Ligand specificities

Harry Brumer: /* Ligand specificities */

2018-02-27T01:55:57Z

Ligand specificities

Harry Brumer at 01:51, 27 February 2018

2018-02-27T01:51:29Z

Harry Gilbert at 15:23, 26 February 2018

2018-02-26T15:23:43Z

Harry Gilbert at 15:23, 26 February 2018

2018-02-26T15:23:09Z

Harry Gilbert at 11:57, 26 February 2018

2018-02-26T11:57:04Z

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 <!-- RESPONSIBLE CURATORS: Please replace the {{UnderConstruction}} tag below with {{CuratorApproved}} when the page is ready for wider public consumption -->
 {{CuratorApproved}}
-* [[Author]]: ^^^Immacolata Venditto^^^
+* [[Author]]: [[User:Immacolata Venditto|Immacolata Venditto]]
-* [[Responsible Curator]]:  ^^^Harry Gilbert^^^
+* [[Responsible Curator]]:  [[User:Harry Gilbert|Harry Gilbert]]
 ----

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 <!-- This is the end of the table -->
 == Ligand specificities ==
-CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from [[GH5]]_4 and [[GH26]], respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration calorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however, CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) relative to cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
+CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from [[GH5]]_4 and [[GH26]], respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration calorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however, CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) relative to cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a [[Carbohydrate-binding_modules#Types|type B]] CBM family.
 == Structural Features ==

@@ Line 16: / Line 16: @@
 <!-- This is the end of the table -->
 == Ligand specificities ==
-CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from [[GH5]]_4 and [[GH26]], respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration calorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however, CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) than cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
+CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from [[GH5]]_4 and [[GH26]], respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration calorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however, CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) relative to cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
 == Structural Features ==

@@ Line 16: / Line 16: @@
 <!-- This is the end of the table -->
 == Ligand specificities ==
-CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from [[GH5]]_4 and [[GH26]], respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration calorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however,CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) than cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
+CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from [[GH5]]_4 and [[GH26]], respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration calorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however, CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) than cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
 == Structural Features ==

@@ Line 16: / Line 16: @@
 <!-- This is the end of the table -->
 == Ligand specificities ==
-CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from [[GH5]]_4 and [[GH26]], respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration caloorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however,CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) than cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
+CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from [[GH5]]_4 and [[GH26]], respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration calorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however,CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) than cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
 == Structural Features ==

@@ Line 16: / Line 16: @@
 <!-- This is the end of the table -->
 == Ligand specificities ==
-CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from GH5_4 and GH26, respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration caloorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however,CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a GH26 “β1,4-mannanase” catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) than cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
+CBM78 is a family identified in the ruminal cellulolytic bacterium ''Ruminococcus flavefaciens'' <cite>RinconMT2010</cite>  cellulosome (a lignocellulose degrading multienzyme complex; see <cite>Fontes2010</cite> for a review of cellulosomes).  The only characterized CBM78 modules are CBM78<sub>RfGH5</sub> and CBM78<sub>RfGH26</sub>, which are components of enzymes containing catalytic modules derived from GH5_4 and GH26, respectively. While the ligand binding of CBM78<sub>RfGH5</sub> was quantified by isothermal titration caloorimetry, the specificity of CBM78<sub>RfGH26</sub> was determined semi-quantitatively using microarrays <cite>VendittoI2016</cite>. Both CBM78 modules bind to β-1,4- and mixed linked β-1,3-1,4-glucans, however,CBM78<sub>RfGH26</sub>, also binds galactomannan and contains a [[GH26]] "β1,4-mannanase" catalytic module <cite>VendittoI2016</cite>. CBM78<sub>RfGH5</sub> displays a higher affinity for xyloglucan relative to cellulose ligands. The similar affinity of CBM78<sub>RfGH5</sub> for cellohexaose and cellopentaose suggests five dominant sugar binding sites. The higher affinity of CBM78<sub>RfGH5</sub>  for the xyloglucan derived oligosaccharide XXXG (where X is a backbone glucose decorated with xylose and G is an unsubstituted glucose) than cellotetraose suggests recognition of the xylose side chains. No binding to regenerated (noncrystalline) insoluble cellulose (RC) was detected. Isothermal titration calorimetry showed that ligand binding was enthalpically driven and coverage of polysaccharides at saturation indicated an endo-mode of binding. CBM78 is thus a type B CBM family.
 == Structural Features ==
 [[File:CBM78_I.V.jpg|thumb|300px|right|'''Figure 1.'''  Crystal structure of CBM78<sub>RfGH5</sub>. ([{{PDBlink}}4V17 PDB ID 4V17]). The aromatic residues that contribute to ligand recognition are shown.]]
 The structure of CBM78<sub>RfGH5</sub> was solved using single-wavelength anomalous diffraction (SAD) methods and selenomethionyl protein to a resolution of 2.0 Å. CBM78<sub>RfGH5</sub> has a β-sandwich fold and contains two β-sheets, 1 and 2, respectively (Figure 1) <cite>VendittoI2016</cite>. β-sheet 2 forms a cleft in which aromatic residues are a dominant feature, typical of many type B CBM families (see <cite>Boraston2004</cite> for review). Trp496, Trp554, Tyr555, and Phe479 are aligned along the cleft. This hydrophobic region is the glucan binding site in CBM78<sub>RfGH5</sub> <cite>VendittoI2016</cite>.
 == Functionalities ==
+CBM78 modules play an enzyme-targeting role that is specific to the ''Ruminococcus'', which has a particularly complex repertoire of scaffoldins (cellulosome assembly proteins) <cite>Bensoussan2017</cite>. The specificity of CBM78<sub>RfGH5</sub> for β-glucans is consistent with the endo-β1,4-glucanase activity of the cognate [[GH5]]_4 catalytic module <cite>Aspeborg2012</cite>. Similarly, the capacity of CBM78<sub>RfGH5</sub> to bind &beta;-mannan is consistent with the appended [[GH26]] catalytic module, a family in which the characterized enzymes are predominantly &beta;1,4-mannanases (e.g. <cite>Hogg2003,Bagenholm2017</cite> and see <cite>Gilbert2008,Gilbert2010</cite> for reviews). Mutagenesis experiments <cite>VendittoI2016</cite> confirmed the importance of the aromatic residues in ligand recognition of CBM78<sub>RfGH5</sub>. Alanine substitution of Trp496 or Trp554 in CBM78<sub>RfGH5</sub>, which are conserved in the CBM family, resulted in complete loss of binding to all ligands. The mutants F479A and Y555A bound to xyloglucan, but not to barley β-glucan or hydroxyethylcellulose (HEC). The variant Q552A recognized xyloglucan and barley β-glucan, but not HEC. No binding to regenerated (noncrystalline) insoluble cellulose was detected consistent with the narrow binding cleft of CBM78<sub>RfGH5</sub> <cite>VendittoI2016</cite>.The mutagenesis data show that different residues play distinct roles in ligand recognition, explaining why this CBM can bind to a range of β-glucans.
 == Family Firsts ==
@@ Line 34: / Line 32: @@
 == References ==
 <biblio>
 #Fontes2010 pmid=20373916
 #RinconMT2010 pmid=20814577
 #VendittoI2016 pmid=27298375
 #Boraston2004 pmid=15214846
 #Bensoussan2017 pmid=27712009
 #Aspeborg2012 pmid=22992189
 #Hogg2003 pmid=12523937
 #Bagenholm2017 pmid=27872187
 #Gilbert2010 pmid=20406913
+#Gilbert2008 pmid=18430603
 </biblio>
 [[Category:Carbohydrate Binding Module Families|CBM078]]

@@ Line 25: / Line 25: @@
 == Functionalities ==
-CBM78 modules play an enzyme-targeting role that is specific to the ''Ruminococcus'', which has a particularly complex repertoire of scaffoldins (cellulosome assembly proteins) Bensoussan2017. The specificity of CBM78<sub>RfGH5</sub> for β-glucans is consistent with the endo-β1,4-glucanase activity of the cognate GH5_4 catalytic module Aspeborg2012. Similarly, the capacity of CBM78<sub>RfGH5</sub> to bind &beta;-mannan is consistent with the appended GH26 catalytic module, a family in which the characterized enzymes are &beta;1,4-mannanases (e.g. Hogg2003,Bågenholm2017 and see Gilbert2010 for review). Mutagenesis experiments <cite>VendittoI2016</cite>confirmed the importance of the aromatic residues in ligand recognition of CBM78<sub>RfGH5</sub>. Alanine substitution of Trp496 or Trp554 in CBM78<sub>RfGH5</sub>, which are conserved in the CBM family, resulted in complete loss of binding to all ligands. The mutants F479A and Y555A bound to xyloglucan, but not to barley β-glucan or hydroxyethylcellulose (HEC).The variant Q552A recognized xyloglucan and barley β-glucan, but not HEC. No binding to regenerated (noncrystalline) insoluble cellulose was detected consistent with the narrow binding cleft of CBM78<sub>RfGH5</sub>.The mutagenesis data show that different residues play distinct roles in ligand recognition, explaining why this CBM can bind to a range of β-glucans.
+CBM78 modules play an enzyme-targeting role that is specific to the ''Ruminococcus'', which has a particularly complex repertoire of scaffoldins (cellulosome assembly proteins) Bensoussan2017. The specificity of CBM78<sub>RfGH5</sub> for β-glucans is consistent with the endo-β1,4-glucanase activity of the cognate GH5_4 catalytic module Aspeborg2012. Similarly, the capacity of CBM78<sub>RfGH5</sub> to bind &beta;-mannan is consistent with the appended GH26 catalytic module, a family in which the characterized enzymes are &beta;1,4-mannanases (e.g. Hogg2003,Bågenholm2017 and see Gilbert2010 for review). Mutagenesis experiments <cite>VendittoI2016</cite> confirmed the importance of the aromatic residues in ligand recognition of CBM78<sub>RfGH5</sub>. Alanine substitution of Trp496 or Trp554 in CBM78<sub>RfGH5</sub>, which are conserved in the CBM family, resulted in complete loss of binding to all ligands. The mutants F479A and Y555A bound to xyloglucan, but not to barley β-glucan or hydroxyethylcellulose (HEC).The variant Q552A recognized xyloglucan and barley β-glucan, but not HEC. No binding to regenerated (noncrystalline) insoluble cellulose was detected consistent with the narrow binding cleft of CBM78<sub>RfGH5</sub> <cite>VendittoI2016</cite>.The mutagenesis data show that different residues play distinct roles in ligand recognition, explaining why this CBM can bind to a range of β-glucans.
 == Family Firsts ==