Histidine aminotransferase activity inStreptomyces tendaeand its correlation with nikkomycin production

Abstract

Streptomyces tendae Tü901 produces nikkomycins belonging to the nucleoside peptide antibiotics. Mutants defective in histidine catabolism were isolated and characterized with regard to their histidine ammonium‐lyase activity and antibiotic synthesis. In the histidine ammonialyase‐negative mutant hut‐11 which was unimpaired in nikkomycin production histidine amino‐transferase activity was detected as an additional histidine metabolizing enzyme. A protein exhibiting histidine aminotransferase activity could be demonstrated on non‐denaturing gels of hut‐11 crude extracts. Using optimized assay conditions, histidine aminotransferase activity was investigated in the strain hut‐11 during growth in nikkomycin production medium. Maximal activity was reached at the end of exponential growth prior to nikkomycin production. In the presence of bromopyruvate, an effective inhibitor of histidine aminotransferase activity in vitro, production of nikkomycin Z and X was markedly reduced in hut‐11.

Purification and characterization of L-histidine aminotransferase from nikkomycin-producing Streptomyces tendae Tu901

“…tendae Tug0 1 /hut-I I separated on polyacrylamide gels, we detected a protein exhibiting transaminase activity with L-histidine in the presence of pyridoxal phosphate and pyruvate (Roos et al, 1992). This protein did not use aromatic amino acids as amino substrates.…”

“…3 ; Kendrick & Wheelis, 1982). In addition to histidase, an aminotransferase with a narrow substrate specificity for Lhistidine as amino donor has been found in nikkomycinproducing S. tendae (Roos et al, 1992). Since histidine is known to be the precursor of the imidazolone base of nikkomycins (Schmidt & Pape, 1985), we investigated whether there is a correlation between formation of HisAT and nikkomycin production.…”

“…tendae Tu901/8c was obtained from the Streptomyces Culture Collection of the Institute of Microbiology I, University of Tiibingen, Germany. S. tendae Tu901/ hut-ll is a histidine-ammonia-lyase-negative mutant (Roos et al, 1992) and Tug0 1 /NP9, NP47 and NP55 are nikkomycin non-producing mutants (Bormann et For nikkomycin production, mycelia were grown in SM medium consisting of 3 YO (w/v) mannitol, 1 % (w/v) starch, 2 % (w/v) soy bean meal, and 1 YO (w/v) yeast extract, pH 40, and in SP medium (3 YO mannitol, 1 YO soluble starch, 0.5% soy peptone and 0.8 % yeast extract, pH 6.0). S. lividans was grown in CRM medium (Bormann et al, 1990) and YEME (Hopwood et al, 1985).…”

“…Electrophoresis using native polyacrylamide gradient gels has been described by Roos et al (1992). The staining method for aminotransferase activity described by Gelfand et al (1977) and Paris & Magasanik (198 1 a) was modified.…”

The biosynthesis of plant alkaloids and nitrogenous microbial metabolites

“…the keto-acid (149) may be a biosynthetic intermediate. 96 The biosynthesis of polyoxins, e.g. polyoxin C [(150), R = CH20H], is clearly similar to that of nikkomycins, e.g.…”