Home >

news Help

Publication Information


Title
Japanese: 
English:Nascent SecM chain interacts with outer ribosomal surface to stabilize translation arrest. 
Author
Japanese: Mikihisa Muta, Ryo Iizuka, 丹羽達也, Yuanfang Guo, 田口英樹, Takashi Funatsu.  
English: Mikihisa Muta, Ryo Iizuka, Tatsuya Niwa, Yuanfang Guo, Hideki Taguchi, Takashi Funatsu.  
Language English 
Journal/Book name
Japanese:The Biochemical journal 
English:The Biochemical journal 
Volume, Number, Page Vol. 477    No. 2    pp. 557-566
Published date Jan. 2020 
Publisher
Japanese: 
English: 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL https://europepmc.org/articles/PMC6993859
 
DOI https://doi.org/10.1042/bcj20190723
Abstract SecM, a bacterial secretion monitor protein, posttranscriptionally regulates downstream gene expression via translation elongation arrest. SecM contains a characteristic amino acid sequence called the arrest sequence at its C-terminus, and this sequence acts within the ribosomal exit tunnel to stop translation. It has been widely assumed that the arrest sequence within the ribosome tunnel is sufficient for translation arrest. We have previously shown that the nascent SecM chain outside the ribosomal exit tunnel stabilizes translation arrest, but the molecular mechanism is unknown. In this study, we found that residues 57-98 of the nascent SecM chain are responsible for stabilizing translation arrest. We performed alanine/serine-scanning mutagenesis of residues 57-98 to identify D79, Y80, W81, H84, R87, I90, R91, and F95 as the key residues responsible for stabilization. The residues were predicted to be located on and near an α-helix-forming segment. A striking feature of the α-helix is the presence of an arginine patch, which interacts with the negatively charged ribosomal surface. A photocross-linking experiment showed that Y80 is adjacent to the ribosomal protein L23, which is located next to the ribosomal exit tunnel when translation is arrested. Thus, the folded nascent SecM chain that emerges from the ribosome exit tunnel interacts with the outer surface of the ribosome to stabilize translation arrest.

©2007 Tokyo Institute of Technology All rights reserved.