Oxetin, a new antimetabolite from an actinomycete. Fermentation, isolation, structure and biological activity

A new amino acid-antimetabolite, oxetin, was isolated from a fermentation broth of a Streptomyces sp. OM-2317, a soil isolate. The chemical structure was elucidated as (2R,3S)-3-amino-2-oxetane carboxylic acid by analysis of the spectral data and by X-ray diffraction methods. The antibiotic is the first natural product possessing an oxetane ring. Certain microorganisms were inhibited by oxetin only when cultivated in minimal media. The inhibitory action was reversed by several amino acids such as L-isoleucine, L-methionine, L-valine and L-glutamine. It also exhibited herbicidal activity and inhibited glutamine synthetase from spinach leaves.