Peptide antibiotic K-582 production in relation to amino acid metabolism in Metarrhizium anisopliae.

Abstract

Formation of the basic antibiotic, K-582 was stimulated by supplying Metarrhiziumi anisopliae U-47 with several amino acids present in its structure. The addition of L-arginine to the basal medium resulted in the almost exclusive formation of K-582 B, while L-lysine increased K-582 A formation. Some carbon sources were observed to have effects similar to those obtained with the above mentioned amino acids. Furthermore, when L-arginine was added in excess to the basal medium, free)"-hydroxyarginine, which is a major constituent of the antibiotic, accumulated extra-and intra-cellularly. Free r-hydroxyarginine isolated from the culture broth of this microorganism was the threo-L-isomer. K-582 formation was repressed by glycerol, which exerted catabolite repression of i'hydroxyarginine synthesis. Imperfect fungus, Metarrhizium anisopliae (Metsch) Sorok var. anisopliae, produces the basic peptide antibiotics, K-582 A and B, which are excreted into the medium; those are effective against yeasts and certain viruses.') Their chemical structures were determined2:: K-582 A is Arg-Hyarg-Orn-Thr-Orn-Lys-Tyr; and K-582 B is Arg-Hyarg-Orn-Thr-Orn-Hyarg-Tyr*. r-Hydroxyarginine present in K-582 A and B, was isolated from a microbe for the first time, but has been known to be present in the sea cucumber, Polycheira rufescens3), the sea anemone, Anthopleura japonica Verrill4), and the seeds of 17 species of the genus Vicia5. Recently, MIZUSAKI and MAKISUMIB> synthesized chemically four stereoisomers of Hyarg via histidine. On the other hand, ITO-KAGAWA, one of the authors reported that in biogenesis of another peptide antibiotic, colistin, by Bacillus colistinus Koyama, yields increased markedly when amino acids of the aspartate family (isoleucine, threonine and a,r-diaminobutyric acid) were added." Specifically, a,rdiaminobutyric acid, a major constituent of the colistin molecule, stimulated colistin biosynthesis, and considerably inhibited the biosynthesis of cellular protein.') The present paper deals with the biogenesis of K-582 in relation to amino acid metabolism and, particularly, the role of Hyarg in the synthesis of K-582. In addition, free Hyarg, which accumulated extra-and intra-cellularly, was isolated and its chemical structure was elucidated. Methods Microorganism Metarrhizium anisopliae U-47, a mutant producing high yields of K-582 and Hyarg and derived from Metarrhizium anisopliae (Metsch) Sorok var. anisopliae strain No. 582M was used throughout this