Direct kinetic comparison of the two cellobiohydrolases Cel6A and Cel7A from Hypocrea jecorina

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

Cellulose degrading fungi such as Hypocrea jecorina secrete several cellulases including the two cellobiohydrolases (CBHs) Cel6A and Cel7A. The two CBHs differ in catalytic mechanism, attack different ends, belong to different families, but are both processive multi-domain enzymes that are essential in the hydrolysis of cellulose. Here we present a direct kinetic comparison of these two enzymes acting on insoluble cellulose. We used both continuous- and end-point assays under either enzyme- or substrate excess, and found distinct kinetic differences between the two CBHs. Cel6A was catalytically superior with a maximal rate over four times higher than Cel7A. Conversely, the ability of Cel6A to attack diverse structures on the cellulose surface was inferior to Cel7A. This latter difference was pronounced as the density of attack sites for Cel7A was almost an order of magnitude higher compared to Cel6A. We conclude that Cel6A is a fast but selective enzyme and that Cel7A is slower, but promiscuous. One consequence of this is that Cel6A is more effective when substrate is plentiful, while Cel7A excels when substrate is limiting. These diverse kinetic properties of Cel6A and Cel7A might elucidate why both cellobiohydrolases are prominent in cellulolytic degrading fungi.
OriginalsprogEngelsk
TidsskriftB B A - Proteins and Proteomics
Vol/bind1865
Udgave nummer12
Sider (fra-til)1739-1745
Antal sider7
ISSN1570-9639
DOI
StatusUdgivet - dec. 2017

Emneord

  • Cel6A
  • Cel7A
  • Cellobiohydrolase
  • Cellulose
  • Hydrolysis
  • Kinetics

Citer dette

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title = "Direct kinetic comparison of the two cellobiohydrolases Cel6A and Cel7A from Hypocrea jecorina",
abstract = "Cellulose degrading fungi such as Hypocrea jecorina secrete several cellulases including the two cellobiohydrolases (CBHs) Cel6A and Cel7A. The two CBHs differ in catalytic mechanism, attack different ends, belong to different families, but are both processive multi-domain enzymes that are essential in the hydrolysis of cellulose. Here we present a direct kinetic comparison of these two enzymes acting on insoluble cellulose. We used both continuous- and end-point assays under either enzyme- or substrate excess, and found distinct kinetic differences between the two CBHs. Cel6A was catalytically superior with a maximal rate over four times higher than Cel7A. Conversely, the ability of Cel6A to attack diverse structures on the cellulose surface was inferior to Cel7A. This latter difference was pronounced as the density of attack sites for Cel7A was almost an order of magnitude higher compared to Cel6A. We conclude that Cel6A is a fast but selective enzyme and that Cel7A is slower, but promiscuous. One consequence of this is that Cel6A is more effective when substrate is plentiful, while Cel7A excels when substrate is limiting. These diverse kinetic properties of Cel6A and Cel7A might elucidate why both cellobiohydrolases are prominent in cellulolytic degrading fungi.",
keywords = "Cel6A, Cel7A, Cellobiohydrolase, Cellulose, Hydrolysis, Kinetics, Cel6A, Cel7A, Cellobiohydrolase, Cellulose, Hydrolysis, Kinetics",
author = "Badino, {Silke Flindt} and Jeppe Kari and Christensen, {Stefan Jarl} and Kim Borch and Peter Westh",
year = "2017",
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journal = "B B A - Proteins and Proteomics",
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Direct kinetic comparison of the two cellobiohydrolases Cel6A and Cel7A from Hypocrea jecorina. / Badino, Silke Flindt; Kari, Jeppe; Christensen, Stefan Jarl; Borch, Kim; Westh, Peter.

I: B B A - Proteins and Proteomics, Bind 1865, Nr. 12, 12.2017, s. 1739-1745.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Direct kinetic comparison of the two cellobiohydrolases Cel6A and Cel7A from Hypocrea jecorina

AU - Badino, Silke Flindt

AU - Kari, Jeppe

AU - Christensen, Stefan Jarl

AU - Borch, Kim

AU - Westh, Peter

PY - 2017/12

Y1 - 2017/12

N2 - Cellulose degrading fungi such as Hypocrea jecorina secrete several cellulases including the two cellobiohydrolases (CBHs) Cel6A and Cel7A. The two CBHs differ in catalytic mechanism, attack different ends, belong to different families, but are both processive multi-domain enzymes that are essential in the hydrolysis of cellulose. Here we present a direct kinetic comparison of these two enzymes acting on insoluble cellulose. We used both continuous- and end-point assays under either enzyme- or substrate excess, and found distinct kinetic differences between the two CBHs. Cel6A was catalytically superior with a maximal rate over four times higher than Cel7A. Conversely, the ability of Cel6A to attack diverse structures on the cellulose surface was inferior to Cel7A. This latter difference was pronounced as the density of attack sites for Cel7A was almost an order of magnitude higher compared to Cel6A. We conclude that Cel6A is a fast but selective enzyme and that Cel7A is slower, but promiscuous. One consequence of this is that Cel6A is more effective when substrate is plentiful, while Cel7A excels when substrate is limiting. These diverse kinetic properties of Cel6A and Cel7A might elucidate why both cellobiohydrolases are prominent in cellulolytic degrading fungi.

AB - Cellulose degrading fungi such as Hypocrea jecorina secrete several cellulases including the two cellobiohydrolases (CBHs) Cel6A and Cel7A. The two CBHs differ in catalytic mechanism, attack different ends, belong to different families, but are both processive multi-domain enzymes that are essential in the hydrolysis of cellulose. Here we present a direct kinetic comparison of these two enzymes acting on insoluble cellulose. We used both continuous- and end-point assays under either enzyme- or substrate excess, and found distinct kinetic differences between the two CBHs. Cel6A was catalytically superior with a maximal rate over four times higher than Cel7A. Conversely, the ability of Cel6A to attack diverse structures on the cellulose surface was inferior to Cel7A. This latter difference was pronounced as the density of attack sites for Cel7A was almost an order of magnitude higher compared to Cel6A. We conclude that Cel6A is a fast but selective enzyme and that Cel7A is slower, but promiscuous. One consequence of this is that Cel6A is more effective when substrate is plentiful, while Cel7A excels when substrate is limiting. These diverse kinetic properties of Cel6A and Cel7A might elucidate why both cellobiohydrolases are prominent in cellulolytic degrading fungi.

KW - Cel6A

KW - Cel7A

KW - Cellobiohydrolase

KW - Cellulose

KW - Hydrolysis

KW - Kinetics

KW - Cel6A

KW - Cel7A

KW - Cellobiohydrolase

KW - Cellulose

KW - Hydrolysis

KW - Kinetics

U2 - 10.1016/j.bbapap.2017.08.013

DO - 10.1016/j.bbapap.2017.08.013

M3 - Journal article

VL - 1865

SP - 1739

EP - 1745

JO - B B A - Proteins and Proteomics

JF - B B A - Proteins and Proteomics

SN - 1570-9639

IS - 12

ER -