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Starvation‐induced expression of SspA and SspB: the effects of a null mutation in sspA on Escherichia coli protein synthesis and survival during growth and prolonged starvation
Author(s) -
Williams Mark D.,
Ouyang Tracy X.,
Flickinger Michael C.
Publication year - 1994
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1994.tb00381.x
Subject(s) - biology , mutant , escherichia coli , starvation , gene , methionine , microbiology and biotechnology , gene expression , biochemistry , amino acid , endocrinology
Summary Maxicell labelling and two‐dimensional gel electro‐phoresis (2‐D PAGE) have identified the proteins encoded by sspA and sspB (SspA, SspB) as proteins D27.1 and A25.8, respectively, in the Escherichia coli gene‐protein database. SspA expression increases with decreasing growth rate and is induced by glucose, nitrogen, phosphate or amino acid starvation. The promoter, P ssp , is similar to gearbox promoters. Inactivation of SspA ( sspA::neo ) blocks sspB expression. [ 35 S]‐methionine‐labelled proteins synthesized during growth and during stationary phase are different in δ sspA strains compared to sspA strains. This difference is enhanced during extended stationary phase (24–72 h). Long‐term (10 d) viability of arginine‐starved isogenic strains shows that sspA cultures remain viable significantly longer than δ sspA mutants. 2‐D PAGE of proteins expressed during exponential growth shows that expression of at least 11 proteins is altered in δ sspA strains. A functional relA gene is required for sspA to affect protein synthesis.