Search results for " actinomycetes"
showing 2 items of 12 documents
Guanosine 5'-diphosphate 3'-diphosphate (ppGpp) as a negative modulator of polynucleotide phosphorylase activity in a 'rare' actinomycete.
2010
Abstract With the beginning of the idiophase the highly phosphorylated guanylic nucleotides guanosine 5'-diphosphate 3'-diphosphate (ppGpp) and guanosine 5'-triphosphate 3'-diphosphate (pppGpp), collectively referred to as (p)ppGpp, activate stress survival adaptation programmes and trigger secondary metabolism in actinomycetes. The major target of (p)ppGpp is the RNA polymerase, where it binds altering the enzyme activity. In this study analysis of the polynucleotide phosphorylase (PNPase)-encoding gene pnp mRNA, in Nonomuraea sp. ATCC 39727 wild-type, constitutively stringent and relaxed strains, led us to hypothesize that in actinomycetes (p)ppGpp may modulate gene expression at the leve…
Regulation of the biosynthesis of the glycopeptide antibiotic A40926 in Nonomuraea ATCC39727
2011
The actinomycete Nonomuraea produces the glycopeptide A40926, precursor of dalbavancin. Dalbavancin is a novel lipoglycopeptide agent against emerging resistant Gram-positive cocci with superior pharmacodynamics properties compared to vancomycin. Chemically, a glycopeptide antibiotic consists of a heptapeptide core constituted by proteinogenic and nonproteinogenic amino acids such as 3,5-dihydroxyphenylglycine (DPG) and 4-hydroxyphenylglycine (HPG). The heptapeptide is assembled by a nonribosomal peptide synthetase and modified by oxidative cross-linking of the electron-rich aromatic side chains, halogenation, sulfation, methylation, acylation, and glycosylation. The A40926 biosynthetic gen…