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Phosphorylation of bacterial L9 and its functional implication in response to starvation stress
Author(s) -
Pei Hairun,
Han Shengnan,
Yang Shaoyuan,
Lei Zhen,
Zheng Jimin,
Jia Zongchao
Publication year - 2017
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.12840
Subject(s) - phosphorylation , ctd , microbiology and biotechnology , biology , escherichia coli , chemistry , biochemistry , gene , geology , oceanography
The bacterial L9 ( bL 9) protein expressed and purified from Escherichia coli is stably phosphorylated. We mapped seven Ser/Thr phosphorylation sites, all of which but one are located at the carboxyl‐terminal domain ( CTD ). When a histidine tag is fused to the C‐terminus, bL 9 is no longer phosphorylated. Phosphorylation of bL 9 causes complete disordering of its CTD and helps cell survival under nutrient‐limiting conditions. Previous structural studies of the ribosome have shown that bL 9 exhibits two distinct conformations, one of which competes with binding of RelA to the 30s rRNA and prevents RelA activation. Taken together, we suggest that the flexibility of the bL 9 CTD enabled by phosphorylation would remove the steric hindrance, serving as a previously unknown mechanism to regulate RelA function and help cell survival under starvation stress.