Antibiotic GE2270 A: A novel inhibitor of bacterial protein synthesis. I. Isolation and characterization.

Abstract

Anovel antibiotic, GE2270A, was isolated from the fermentation broth of a strain of Planobispora rosea. The product was found to inhibit bacterial protein synthesis. Structural characteristics showed similarities between GE2270 A and thiazolyl peptides such as micrococcin which is known to inhibit protein synthesis by acting directly on the ribosome. Despite this similarity GE2270A showed functional analogy to kirromycin-like antibiotics and pulvomycin, as its molecular target was found to be elongation factor Tu (EF-Tu). GE2270A is active against Gram-positive microorganism and anaerobes and differs from the other EF-Tu inhibitors in its spectrum of antimicrobial activity. 693 GE2270A, a novel peptide antibiotic, emerged from a screening program designed to detect inhibitors of protein synthesis. The present paper deals with the discovery, isolation, initial physico-chemical and biological characterization of this antibiotic. Materials and Methods Cultural and Growth Characteristics of the Producing Strain Colonial and morphological characters were determined with standard methods1'2*. Color determination was madeaccording to Maerz and Paul3). Growthon sole sources of carbon was determined after incubation at 28°C for 2 weeks1*. Chemotaxonomic Characteristics of the Producing Strain Freeze-dried biomass was examined to determine the major chemotaxonomiccharacteristics. Cell wall diamino acids were determined by TLCby a modification of the method of Becker et a/.4)5). Wholecell sugars were hydrolyzed, reduced and derivatized. The resultant alditol acetates were analyzed by GC6). Fatty acid methyl esters were similarly analyzed by GC7). Menaquinones and polar lipids were extracted and analyzed by HPLCand 2D TLC, respectively8*. Fermentation of the Producing Strain A 500-ml Erlenmeyer flask containing 100 ml of seed medium (Pdlypeptone 0.5%, yeast extract 0.3%, beef extract 0.2%, soybean meal 0.2%, starch 2%, calcium carbonate 1%, pH 7.0) was inoculated from an oatmeal slant of the producing strain. After incubation at 28°C for 96 hours on a rotary shaker (200 rpm), the biomass was transferred to a 10-liter jar fermenter containing 4 liters of the seed medium. This culture was grown for 72 hours at 28°C with 2 liters/minute air flow and stirring at 900rpm, prior to inoculating a jar fermenter containing 50 liters of production medium(starch 2%, peptone 0.25%,

Induction of antimicrobial activities in heterologous streptomycetes using alleles of the Streptomyces coelicolor gene absA1

“…17 Consistent with our screening results, we found that the MIC against B. cenocepacia and B. vietnamiensis was 8 mg ml À1 . The purified molecule also exerted activity (MICs of 16-32 mg ml À1 ) against P. aeruginosa and Acinetobacter baumannii (ATCC 17978), two other opportunistic pathogens that are highly antibiotic resistant.…”

Changes in GE2270 antibiotic production in Planobispora rosea through modulation of methylation metabolism

“…GE2270 is a novel potent antibiotic inhibiting protein synthesis in Gram-positive bacteria (Goldstein et al, 1993;Selva et al, 1991). It is the natural precursor of clinical candidate BI-K0376 specifically active against Propionibacterium acnes, including isolates resistant to currently available therapies (Jabes et al, 2002).…”

Sensitivity of elongation factor Tu (EF-Tu) from different bacterial species to the antibiotics efrotomycin, pulvomycin and MDL 62879

“…l), in the nature of their interaction with EF-Tu (Fasano et al, 1978;Wolf et al, 1974;Anborgh & Parmeggiani, 1991) and in their spectrum of antibacterial activity (Selva et al,199 1). All three antibiotics are natural products : kirromycins and pulvomycin are produced by different species of Streptomyces, MDL 62 879 by Planobispora rosea (Parmeggiani & Swart, 1985;Akita et al, 1963;Selva et al, 1991).…”

“…MDL 62879 is active against Grampositive bacteria (Selva et al, 1991). Kirromycins are not active against some species of Gram-positive bacteria such as Bacillus subtilis, staphylococci and enterococci, but they are active against some Gram-negative bacteria such as Neisseria gonorrhoeae and Haemophilus influenzae (Frost et al, 1976(Frost et al, , 1979 on which MDL 62879 has little or no activity.…”