Open AccessCharacterization of a bifunctional enzyme with (p)pp G pp‐hydrolase/synthase activity in L eptospira interrogans
Author(s) -
He Ping,
Deng Cong,
Liu BoYu,
Zeng LingBing,
Zhao Wei,
Zhang Yan,
Jiang XuCheng,
Guo XiaoKui,
Qin JinHong
Publication year - 2013
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/1574-6968.12279
Subject(s) - stringent response , escherichia coli , biochemistry , leptospira interrogans , enzyme , atp synthase , mutant , phosphofructokinase 2 , biology , hydrolase , bacteria , guanosine , chemistry , microbiology and biotechnology , gene , genetics , leptospira , serotype
Alarmone Guanosine 5′‐diphosphate (or 5′‐triphosphate) 3′‐diphosphate [(p)pp G pp] is the key component that globally regulates stringent control in bacteria. There are two homologous enzymes, R el A and S po T in E scherichia coli , which are responsible for fluctuations in (p)pp G pp concentration inside the cell, whereas there exists only a single R el A / S po T enzyme in Gram‐positive bacteria. We have identified a bifunctional enzyme with (p)pp G pp‐hydrolase/synthase activity in L eptospira interrogans . We show that the rel Lin gene ( LA _3085) encodes a protein that fully complements the rel A / spo T double mutants in E . coli . The protein functions as a (p)pp G pp degradase as well as a (p)pp G pp synthase when the cells encounter amino acid stress and deprivation of carbon sources. N ‐terminus HD and RSD domains of rel Lin ( rel LinN ) were observed to restore growth of double mutants of E . coli . Finally, We demonstrate that purified R el Lin and R el LinN show high (p)pp G pp synthesis activity in vitro . Taken together, our results suggest that L . interrogans contain a single Rel‐like bifunctional protein, R el Lin , which plays an important role in maintaining the basal level of (p)pp G pp in the cell potentially contributing to the regulation of bacterial stress response.