title: Linker length and flexibility induces new cellobiohydrolase activity of PoCel6A from Penicillium oxalicum.
abstract: In a previous study, a novel cellobiohydrolase, PoCel6A, with new enzymatic activity against p-nitrophenyl-β-D-cellobioside (pNPC), 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 pNPC 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.
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, PR China.|Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors: Le
authors: L
authors: Gao
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, PR China.
authors: Lushan
authors: L
authors: Wang
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, PR China.
authors: Xukai
authors: X
authors: Jiang
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, PR China. quyinbo@sdu.edu.cn.
authors: Yinbo
authors: Y
authors: Qu
mesh_terms: D000595:Amino Acid Sequence; D043366:Cellulose 1,4-beta-Cellobiosidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010407:Penicillium / Q000201:enzymology* / Q000235:genetics; D018583:Pliability; D015202:Protein Engineering; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D005656:Fungal Proteins; D011994:Recombinant Proteins; D043366:Cellulose 1,4-beta-Cellobiosidase
keywords: Cel6A; Penicillium oxalicum; linker flexiblity; linker length