Lantibiotic biosynthetic gene clusters from A. garbadinensis and A. Liguriae

A compound of the formula:

• wherein:
• -X1-X2- represent -Leu-Val-, -Val-Val- or -Leu-Ile-;
• Y is —S— or —S(O)—;
• Z is either —NH2 or an amino acid;
• and
• R represents the group —OH or —NR1R2, wherein R1 and R2 independently represent:
• (i) hydrogen;
• (ii) a group of formula —(CH2)n—NR3R4, in which n represents an integer from 2 to 8 and R3 and R4 independently represent hydrogen or (C1-C4) alkyl, or R3 and R4 taken together represent —(CH2)3—, —(CH2)4—, (CH2)2—O—(CH2)2—, —(CH2)2—S—(CH2)2— or —(CH2)5—;
• or R1 and R2 taken together with the adjacent nitrogen atom represent a piperazine which may be substituted in position 4 with a substituent selected from:
• (a) (C1-C4)alkyl;
• (b) (C5-C7)-cycloalkyl,
• (c) pyridyl,
• (d) —(CH2)p—NR5R6 in which p represents an integer from 1 to 8 and R5 and R6 independently represent hydrogen or (C1-C4) alkyl,
• (e) piperidinyl,
• (f) substituted piperidinyl, wherein the substituted piperidinyl bears a N-substituent which is (C1-4)alkyl,
• (g) benzyl, and
• (h) substituted benzyl, wherein a phenyl therein bears 1 or 2 substituents selected from chloro, bromo, nitro, (C1-C4)alkyl and (C1-C4)alkoxy;
• or a biologically active variant thereof wherein 1, 2, 3 or 4 amino acids at positions 2, 3, 4, 5, 8, 10, 11, 13 or 18 are substituted by another amino acid, and the another amino acid is a naturally occurring amino acid or its D-isoform, or a pharmaceutically acceptable salt of said compound or variant.