Title |
Cytophaga hutchinsonii chu_2177, encoding the O-antigen ligase, is essential for cellulose degradation |
Author |
Yahong Tan1, Wenxia Song1, Lijuan Gao1,2, Weican Zhang1, and Xuemei Lu1* |
Address |
1State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, P. R. China, 2School of Life Science and Technology, Weifang Medical University, Weifang 261000, P. R. China |
Bibliography |
Journal of Microbiology, 60(4),364-374, 2022,
|
DOI |
10.1007/s12275-022-1531-3
|
Key Words |
Cytophaga hutchinsonii, O-antigen ligase, cellulose
degradation, T9SS cargo proteins, cellulase |
Abstract |
Cytophaga hutchinsonii can efficiently degrade crystalline
cellulose, in which the cell surface cellulases secreted by the
type IX secretion system (T9SS) play important roles, but
the degradation mechanism remains unclear, and the anchor
mechanism of cellulases on the outer membrane in C.
hutchinsonii has not been studied. Here, chu_2177 was identified
by transposon mutagenesis and was proved to be indispensable
for cellulose utilization in C. hutchinsonii. Disruption
of chu_2177 resulted in O-antigen deficiency and chu_
177 could confer O-antigen ligase activity upon an Escherichia
coli waal mutant, indicating that chu_2177 encoded the Ontigen
ligase. Moreover, deletion of chu_2177 caused defects
in cellulose utilization, cell motility, biofilm formation, and
stress resistance. Further study showed that the endoglucanase
activity was markedly decreased in the outer membrane
but was increased in the culture fluid without chu_2177.
Western blot proved that endoglucanase CHU_1336 was not
located on the outer membrane but was released in the culture
fluid of the Δ2177 mutant. Further proteomics analysis
showed that many cargo proteins of T9SS were missing in
the outer membrane of the Δ2177 mutant. Our study revealed
that the deletion of chu_2177 affected the localization of
many T9SS cargo proteins including cellulases on the outer
membrane of C. hutchinsonii. |