Xylan oligosaccharides and cellobiohydrolase I (<it>Tr</it>Cel7A) interaction and effect on activity
<p>Abstract</p> <p>Background</p> <p>The well-studied cellulase mixture secreted by <it>Trichoderma reesei </it>(anamorph to <it>Hypocrea jecorina</it>) contains two cellobiohydolases (CBHs), cellobiohydrolase I (<it>Tr</it>Cel7A) and...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2011-10-01
|
| Series: | Biotechnology for Biofuels |
| Subjects: | |
| Online Access: | http://www.biotechnologyforbiofuels.com/content/4/1/45 |
| _version_ | 1818199883281072128 |
|---|---|
| author | Baumann Martin J Borch Kim Westh Peter |
| author_facet | Baumann Martin J Borch Kim Westh Peter |
| author_sort | Baumann Martin J |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>The well-studied cellulase mixture secreted by <it>Trichoderma reesei </it>(anamorph to <it>Hypocrea jecorina</it>) contains two cellobiohydolases (CBHs), cellobiohydrolase I (<it>Tr</it>Cel7A) and cellobiohydrolase II (<it>Tr</it>CeI6A), that are core enzymes for the solubilisation of cellulose. This has attracted significant research interest because of the role of the CBHs in the conversion of biomass to fermentable sugars. However, the CHBs are notoriously slow and susceptible to inhibition, which presents a challenge for the commercial utilisation of biomass. The xylans and xylan fragments that are also present in the biomass have been suggested repeatedly as one cause of the reduced activity of CHBs. Yet, the extent and mechanisms of this inhibition remain poorly elucidated. Therefore, we studied xylan oligosaccharides (XOSs) of variable lengths with respect to their binding and inhibition of both <it>Tr</it>Cel7A and an enzyme variant without the cellulose-binding domain (CBM).</p> <p>Results</p> <p>We studied the binding of XOSs to <it>Tr</it>Cel7A by isothermal titration calorimetry. We found that XOSs bind to <it>Tr</it>Cel7A and that the affinity increases commensurate with XOS length. The CBM, on the other hand, did not affect the affinity significantly, which suggests that XOSs may bind to the active site. Activity assays of <it>Tr</it>Cel7A clearly demonstrated the negative effect of the presence of XOSs on the turnover number.</p> <p>Conclusions</p> <p>On the basis of these binding data and a comparison of XOS inhibition of the activity of the two enzyme variants towards, respectively, soluble and insoluble substrates, we propose a competitive mechanism for XOS inhibition of <it>Tr</it>Cel7A with phosphoric swollen cellulose as a substrate.</p> |
| first_indexed | 2024-12-12T02:28:50Z |
| format | Article |
| id | doaj.art-5969a83d6ddb45af85f35672f79f0baa |
| institution | Directory Open Access Journal |
| issn | 1754-6834 |
| language | English |
| last_indexed | 2024-12-12T02:28:50Z |
| publishDate | 2011-10-01 |
| publisher | BMC |
| record_format | Article |
| series | Biotechnology for Biofuels |
| spelling | doaj.art-5969a83d6ddb45af85f35672f79f0baa2022-12-22T00:41:28ZengBMCBiotechnology for Biofuels1754-68342011-10-01414510.1186/1754-6834-4-45Xylan oligosaccharides and cellobiohydrolase I (<it>Tr</it>Cel7A) interaction and effect on activityBaumann Martin JBorch KimWesth Peter<p>Abstract</p> <p>Background</p> <p>The well-studied cellulase mixture secreted by <it>Trichoderma reesei </it>(anamorph to <it>Hypocrea jecorina</it>) contains two cellobiohydolases (CBHs), cellobiohydrolase I (<it>Tr</it>Cel7A) and cellobiohydrolase II (<it>Tr</it>CeI6A), that are core enzymes for the solubilisation of cellulose. This has attracted significant research interest because of the role of the CBHs in the conversion of biomass to fermentable sugars. However, the CHBs are notoriously slow and susceptible to inhibition, which presents a challenge for the commercial utilisation of biomass. The xylans and xylan fragments that are also present in the biomass have been suggested repeatedly as one cause of the reduced activity of CHBs. Yet, the extent and mechanisms of this inhibition remain poorly elucidated. Therefore, we studied xylan oligosaccharides (XOSs) of variable lengths with respect to their binding and inhibition of both <it>Tr</it>Cel7A and an enzyme variant without the cellulose-binding domain (CBM).</p> <p>Results</p> <p>We studied the binding of XOSs to <it>Tr</it>Cel7A by isothermal titration calorimetry. We found that XOSs bind to <it>Tr</it>Cel7A and that the affinity increases commensurate with XOS length. The CBM, on the other hand, did not affect the affinity significantly, which suggests that XOSs may bind to the active site. Activity assays of <it>Tr</it>Cel7A clearly demonstrated the negative effect of the presence of XOSs on the turnover number.</p> <p>Conclusions</p> <p>On the basis of these binding data and a comparison of XOS inhibition of the activity of the two enzyme variants towards, respectively, soluble and insoluble substrates, we propose a competitive mechanism for XOS inhibition of <it>Tr</it>Cel7A with phosphoric swollen cellulose as a substrate.</p>http://www.biotechnologyforbiofuels.com/content/4/1/45cellobiohydrolase 1<it>Tr</it>Cel7Axylanxylan oligosaccharidebindinginhibitionbiomass degradationisothermal titration calorimetry |
| spellingShingle | Baumann Martin J Borch Kim Westh Peter Xylan oligosaccharides and cellobiohydrolase I (<it>Tr</it>Cel7A) interaction and effect on activity Biotechnology for Biofuels cellobiohydrolase 1 <it>Tr</it>Cel7A xylan xylan oligosaccharide binding inhibition biomass degradation isothermal titration calorimetry |
| title | Xylan oligosaccharides and cellobiohydrolase I (<it>Tr</it>Cel7A) interaction and effect on activity |
| title_full | Xylan oligosaccharides and cellobiohydrolase I (<it>Tr</it>Cel7A) interaction and effect on activity |
| title_fullStr | Xylan oligosaccharides and cellobiohydrolase I (<it>Tr</it>Cel7A) interaction and effect on activity |
| title_full_unstemmed | Xylan oligosaccharides and cellobiohydrolase I (<it>Tr</it>Cel7A) interaction and effect on activity |
| title_short | Xylan oligosaccharides and cellobiohydrolase I (<it>Tr</it>Cel7A) interaction and effect on activity |
| title_sort | xylan oligosaccharides and cellobiohydrolase i it tr it cel7a interaction and effect on activity |
| topic | cellobiohydrolase 1 <it>Tr</it>Cel7A xylan xylan oligosaccharide binding inhibition biomass degradation isothermal titration calorimetry |
| url | http://www.biotechnologyforbiofuels.com/content/4/1/45 |
| work_keys_str_mv | AT baumannmartinj xylanoligosaccharidesandcellobiohydrolaseiittritcel7ainteractionandeffectonactivity AT borchkim xylanoligosaccharidesandcellobiohydrolaseiittritcel7ainteractionandeffectonactivity AT westhpeter xylanoligosaccharidesandcellobiohydrolaseiittritcel7ainteractionandeffectonactivity |