NOSIHEPTIDE IS A HETROCYCLIC THIOPEPTIDE, CONSISTING OF FIVE THIAZOLES AND ONE 3-HYDROXYPYRIDINE RINGS. A MODIFIED
INDOLE RING NO1(14) IS LINKED VIA THE SIDE CHAINS OF 3-HYDROXY 3GL(6) AND CYS(8). THE OBSERVED C-TERMINAL AMINO GROUP
NH2(13) IS LIKELY TO BE A POST-TRANSLATIONAL DECARBOXYLATED REMNANT OF A SER C-TERMINAL RESIDUE
QUINOMYCIN UK63052 IS A BICYCLIC OCTADEPSIPEPTIDE.
BICYCLIZATION IS ACHIEVED BY LINKING THE N- AND
THE C- TERMINI, AND A THIOACETAL BOND BETWEEN
RESIDUES 3 AND 7.
THE TWO HYDROXYQUINOXALINE CHROMOPHORES ARE LINKED
TO THE D-SERINE RESIDUES, RESIDUES 1 AND 5.
