Open AccessProtein catabolism in growing Bacillus megaterium during adaptation to salt stress
Author(s) -
Nekolny David,
Chaloupka Jiří
Publication year - 2000
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/j.1574-6968.2000.tb09010.x
Subject(s) - bacillus megaterium , catabolism , intracellular , biochemistry , adaptation (eye) , protein turnover , biology , chemistry , microbiology and biotechnology , metabolism , bacteria , protein biosynthesis , genetics , neuroscience
Abstract Elevated concentration of NaCl in liquid medium caused a concentration‐dependent growth delay (adaptation lag) and decrease in the maximal growth rate of Bacillus megaterium . The adaptation to salt stress was accompanied by transformation of some otherwise stable (long‐lived; LLP) cell proteins into quickly degraded (short‐lived; SLP) ones. Exposure to the strongly growth‐reducing 1 M NaCl increased the size of the SLP ‘pool’ of intracellular proteins from about 5 to about 15% of total protein. The major intracellular proteolytic capacity of B. megaterium is represented by intracellular serine proteinases (ISP). Paradoxically, their specific activity was lowered or masked during the adaptation phase marked by increased catabolism of short‐lived and/or destabilized proteins by the stress. This documents that intracellular proteolytic activity cannot be a key regulator of protein catabolism during adaptation to stress.