Production of the antibacterial polypeptide microcin B17 (MccB17) by Escherichia coli ZK650 was inhibited by simulated microgravity. The site of MccB17 accumulation was found to be different, depending on whether the organism was grown in shaking flasks or in rotating bioreactors designed to establish a simulated microgravity environment. In flasks, the accumulation was cellular, but in the rea...

The anti-cancer drug Laetrile is one of the most controversial subjects in the history of medicine. Laetrile's most ardent proponents consider it to be a natural cancer cure, literally built in to the normal "vitamin architecture" of mammalian food supplies as the primary natural exogenous cancer control for humans and animals. They have called Laetrile "vitamin B17."(1) Laetrile's opponents co...

Human relaxin, a two-chain protein hormone, was synthesized by solid-phase peptide synthesis in combination with a novel thiol-protecting group strategy whereby the three disulfide bonds could be synthesized sequentially and without error. The final product was shown to be homogeneous by reversed-phase high performance liquid chromatography and electrophoresis and had the correct amino acid com...

In common with most autoimmune diseases, psoriasis is associated with some HLA antigens. We studied the distribution of HLA antigens in Croatian patients with psoriasis: 108 patients were divided into groups according to family history and age of disease onset. HLA antigens were analyzed serologically and HLA-C alleles were analyzed using polymerase chain reaction. We found significant increase...

To produce the antibiotic Microcin B17, four Cys and four Ser residues are converted into four thiazoles and four oxazoles by the three subunit Microcin B17 synthetase. High-resolution mass spectrometry (MS) was used to monitor the kinetics of posttranslational heterocyclic ring formation (-20 Da per ring) and demonstrated the accumulation of all intermediates, from one to seven rings, indicati...

BACKGROUND The Escherichia coli peptide antibiotic microcin B17 (MccB17) contains four oxazole and four thiazole rings, and inhibits DNA gyrase. The role of individual and tandem pairs of heterocycles in bioactivity has not been determined previously. RESULTS The two tandem 4,2-bisheterocycles in MccB17 were varied by expression of MccB17 or mutants containing altered sequences at Gly39-Ser40...