Open AccessStudies on the Control of Development
Author(s) -
RHAESE HansJürgen,
DICHTELMÜLLER Herbert,
GRADE Reinhardt
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb02244.x
Subject(s) - stringent response , bacillus subtilis , biochemistry , chloramphenicol , protein biosynthesis , ribosome , guanosine , biology , escherichia coli , rna , chemistry , antibiotics , bacteria , genetics , gene
Bacillus subtilis cells accumulate unusual phosphorylated substances at the end of logarithmic growth in a semi‐synthetic medium. Two of these substances are guanosine 3′(2′)‐diphosphate 5′‐diphosphate (ppGpp) and guanosine 3′(2′)‐diphosphate 5′‐triphosphate (pppGpp) which, in contrast to amino‐acid‐starved Escherichia coli cells, are not degraded in sporulating cells of B. subtilis after the addition of chloramphenicol. Moreover, inhibition of protein synthesis in growing cells of B. subtilis causes accumulation of ppGpp and pppGpp, which is also in contrast to E. coli . This was shown by isolation and characterization of substances produced in these cells after the addition of chloramphenicol. Other inhibitors of protein synthesis acting at the ribosomal level also cause the accumulation of ppGpp and pppGpp. There is no difference between the action of antibiotics affecting 50‐S and/or 30‐S ribosomal subunits, since chloramphenicol, tetracycline, erythromycin and neomycin cause the accumulation of almost equal amounts of these nucleotides. This apparently resolves the close connection between ppGpp accumulation and the rate of stable RNA synthesis, which was believed to exist also in B. subtilis because of the stringent response observed after amino acid starvation coupled with ppGpp accumulation. Antibiotics which inhibit protein synthesis differently than by affecting the ribosomes (puromycin) or which inhibit RNA (rifampicin) or DNA (nalidixic acid) synthesis do not cause ppGpp accumulation. The accumulation of ppGpp and pppGpp in the presence of charged tRNA provided by chloramphenicol treatment suggests that the signal for the synthesis of unusual nucleotides is an inhibition of the binding of tRNA (charged or uncharged) to the acceptor site of the ribosome. This activates the rel gene product which forms ppGpp and pppGpp from GTP and ATP. Sporulating cells of B. subtilis without chloramphenicol treatment produce besides ppGpp and pppGpp other unusual substances, which are likely to be highly phosphorylated nucleotides contained adenine as base moiety.