Abstract:
:Cellulosomes are key for lignocellulosic biomass degradation in cellulolytic Clostridia. Better understanding of the mechanism of cellulosome regulation would allow us to improve lignocellulose hydrolysis. It is hypothesized that cellulosomal protease inhibitors would regulate cellulosome architecture and then lignocellulose hydrolysis. Here, a dockerin-containing protease inhibitor gene (dpi) in Clostridium cellulolyticum H10 was characterized by mutagenesis and physiological analyses. The dpi mutant had a decreased cell yield on glucose, cellulose and xylan, lower cellulose utilization efficiency, and a 70% and 52% decrease of the key cellulosomal components, Cel48F and Cel9E respectively. The decreased cellulolysis is caused by the proteolysis of major cellulosomal components, such as Cel48F and Cel9E. Disruption of cel9E severely impaired cell growth on cellulose while loss of cel48F completely abolished cellulolytic activity. These observations are due to the combinational results of gene inactivation and polar effects caused by intron insertion. Purified recombinant Dpi showed inhibitory activity against cysteine protease. Taken together, Dpi protects key cellulosomal cellulases from proteolysis in H10. This study identified the physiological importance of cellulosome-localized protease inhibitors in Clostridia.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Xu T,Li Y,He Z,Zhou Jdoi
10.1111/mmi.12488subject
Has Abstractpub_date
2014-02-01 00:00:00pages
694-705issue
4eissn
0950-382Xissn
1365-2958journal_volume
91pub_type
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journal_title:Molecular microbiology
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journal_title:Molecular microbiology
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