Ala(0)-actagardine, a New Lantibiotic from Cultures of Actinoplanes liguriae ATCC 31048.

Abstract

The actagardine-producing strain Actinoplanes liguriae ATCC3 1048, forms an additional lantibiotic when it is cultured on mannitol and soya meal. The new compound, Ala(0)-actagardine (1), has been isolated by solid-phase extraction followed by a two-step chromatographic separation. The molecular formula of 1 is C84H129N21O25S4. Its chemical structure was determined by 2D-NMRanalysis and was further confirmed by an amino acid analysis, Edman degradation, and partial synthesis from actagardine. 1 exhibits a slightly higher biological activity than the parent compound actagardine. The synthetic analogs Lys(O)-actagardine (2) and Ile(O)-actagardine (3) demonstrate also antibacterial activities and emphasize the importance of the TV-terminus for further derivatization.

Organization of the genes encoding the biosynthesis of actagardine and engineering of a variant generation system

“…In this instance, cleavage between position −1 and −2 would result in the retention of an alanine residue at the N‐terminus, generating ala(0) variants (m/z +36 for doubly charged ions) of actagardine. Such variants were described by Vértesy et al . (1999) and are routinely observed in the fermentation broths of A. garbadinensis .…”

“…In this instance, cleavage between position -1 and -2 would result in the retention of an alanine residue at the N-terminus, generating ala(0) variants (m/z +36 for doubly charged ions) of actagardine. Such variants were described by Vértesy et al (1999) and are routinely observed in the fermentation broths of A. garbadinensis. The abundance of ala(0) products containing an additional N-terminal alanine residue appears to decrease in prolonged fermentations of A. garbadinensis presumably due to cleavage of the N-terminal alanine.…”

Mechanistic Understanding of Lanthipeptide Biosynthetic Enzymes

“…This modification has only been found in the 19-amino acid globular lanthipeptide actagardine (also known as gardimycin) 452 and Ala(0)-actagardine, which differs from actagardine by a single additional Ala residue at the N-terminus (Figure 42). 453 The structure of actagardine was determined by a combination of Edman sequencing, MS, and NMR analysis, 454−456 revealing that oxidation occurs site-selectivity in the D-ring. 454 The genetic origin of sulfoxide formation was uncovered through a comparison of the gene clusters of actagardine and another lanthipeptide michiganin A, 86 which is similar in structure to actagardine but lacks the sulfoxide.…”

Heterologous production of the lantibiotic Ala(0)actagardine in Escherichia coli

“…7, 8 Ala(0)-actagardine is a natural variant with an additional N-terminal alanine that is produced by Actinoplanes liguriae ATCC 31048. 9 Actagardine possesses potent antimicrobial activity against gram-positive pathogens including Clostridium difficile and is stable in simulated gastric fluid. 10 Actagardine inhibits cell wall biosynthesis by binding to lipid II, 11 and its binding is not antagonized by vancomycin.…”