T. Buchan et al., MUTANTS OF STREPTOMYCES-CATTLEYA DEFECTIVE IN THE SYNTHESIS OF A FACTOR REQUIRED FOR THIENAMYCIN PRODUCTION, Journal of antibiotics, 47(9), 1994, pp. 992-1000
Thienamycin non-producing mutants of Streptomydes cattleya were identi
fied that displayed a cross-feeding relationship. A diffusible product
from one of these mutants (RK-11) resulted in restoration of thienamy
cin production when fed to cultures of another mutant (RK-4). In vivo
radiolabeling experiments were conducted to test whether the RK-11 mut
ant produced a late biosynthetic intermediate which contained a carbap
enem ring and a cysteaminyl and/or a hydroxyethyl side chain. Both [S-
35]cystine and [methyl-H-3]methionine were used to label the RK-11 pro
duct which was then fed to RK-4 cultures. None of the thienamycin subs
equently produced by RK-4 converter cells was labeled, implying the la
ck of either side chain of the thienamycin molecule in the RK-11 produ
ct. Further stability studies suggested that the RK-11 product does no
t contain a carbapenem ring. Additional feeding experiments with RK-4
cells also ruled out the possibility that the RK-11 product is a co-fa
ctor necessary for thienamycin production. It is concluded that the RK
-11 product may regulate expression of the thienamycin gene cluster.