Piceamycin and its N-acetylcysteine adduct is produced by Streptomyces sp. GB 4-2.

Piceamycin, a new macrolactam polyketide antibiotic, was detected by HPLC-diode array screening in extracts of Streptomyces sp. GB 4-2, which was isolated from the mycorrhizosphere of Norway spruce. The structure of piceamycin was determined by mass spectrometry and NMR experiments.

An acyl-CoA dehydrogenase is involved in the formation of the Delta cis3 double bond in the acyl residue of the lipopeptide antibiotic friulimicin in Actinoplanes friuliensis.

The lipopeptide antibiotic friulimicin, produced by Actinoplanes friuliensis, is an effective drug against Gram-positive bacteria, such as methicillin-resistant Staphylococcus epidermidis and Staphylococcus aureus strains. Friulimicin consists of a cyclic peptide core of ten amino acids and an acyl residue linked to an exocyclic amino acid. The acyl residue is essential for antibiotic activity, varies in length from C13 to C15, and carries a characteristic double bond at position Delta cis3.

A unique hydrophobic cluster near the active site contributes to differences in borrelidin inhibition among threonyl-tRNA synthetases.

Borrelidin, a compound with anti-microbial and anti-angiogenic properties, is a known inhibitor of bacterial and eukaryal threonyl-tRNA synthetase (ThrRS). The inhibition mechanism of borrelidin is not well understood. Archaea contain archaeal and bacterial genre ThrRS enzymes that can be distinguished by their sequence.

Profound insights into squalene cyclization.

In this issue of Chemistry & Biology, our understanding of the formation of pentacyclic hopene from the linear squalene is enhanced by an X-ray structure of a complex between squalene-hopene cyclase and the substrate analog 2-azasqualene.

Hopanoids are formed during transition from substrate to aerial hyphae in Streptomyces coelicolor A3(2).

Streptomyces coelicolor A3(2) contains a cluster of putative isoprenoid and hopanoid biosynthetic genes. The strain does not produce the pentacyclic hopanoids in liquid culture but produces them on solid medium when sporulating. Mutants defective in the formation of aerial mycelium and spores (bld), with the exception of bldB, do not synthesize hopanoids, whereas mutants, which form aerial mycelium but no spores (whi), do.