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Linker length and flexibility induces new cellobiohydrolase activity of PoCel6A from Penicillium oxalicum
Author(s) -
Gao Le,
Wang Lushan,
Jiang Xukai,
Qu Yinbo
Publication year - 2015
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.201400734
Subject(s) - linker , chemistry , cellulase , enzyme , cellulose , stereochemistry , thermophile , combinatorial chemistry , substrate (aquarium) , biochemistry , biology , computer science , operating system , ecology
In a previous study, a novel cellobiohydrolase, PoCel6A, with new enzymatic activity against p ‐nitrophenyl‐β‐ D ‐cellobioside ( p NPC), was purified from Penicillium oxalicum. The cellulose‐binding module and catalytic domain of PoCel6A showed a high degree of sequence similarity with other fungal Cel6As. However, PoCel6A had 11 more amino acids in the linker region than other Cel6As. To evaluate the relationship between the longer linker of PoCel6A and its enzymatic activity, 11 amino acids were deleted from the linker region of PoCel6A. The shortened PoCel6A linker nullified the enzymatic activity against p NPC but dramatically increased the enzyme's capacity for crystalline cellulose degradation. The shortened linker segment appeared to have no effect on the secondary structural conformation of PoCel6A. Another variant (PoCel6A‐6pro) with six consecutive proline residues in the interdomain linker had a higher rigid linker, and no enzymatic activity was observed against soluble and insoluble substrate. The flexibility of the linker had an important function in the formation of active cellulase. The length and flexibility of the linker is clearly able to modify the function of PoCel6A and induce new characteristics of Cel6A.