The structure of PA48009: The revised structure of duramycin.

Abstract

PA48009,a lanthionine-containing peptide antibiotic was isolated from the culture broth of Streptoverticillium griseoverticillatum PA-48009, and identified as duramycin. Determination of the structure using both Edmandegradations and 2D NMR spectroscopy showed the need to revise the structure of duramycin given in literature. Duramycin (PA48009) was different from lanthiopeptin (Ro 09-0198, cinnamycin) only by a Lys/Arg exchange at position 2.During screening of new biologically active compounds, PA48009 (1), a lanthionine-containing peptide antibiotic, was isolated from the fermentation broth of Streptoverticillium griseoverticillatum PA-48009. It exhibited weak antimicrobial activity against Gram-positive organisms. Several lanthionine-containing peptide antibiotics have been reported already1~n). Recent development of NMRmethodology and instrumentation12 '13) make it possible to analyze NMRspectra and to determine the conformation of small proteins and oligopeptides. The structure of Ro 09-0198 was reported by Kessler et al.lt8\ but the reported structure showed some discrepancies with that of lanthiopeptin (3) ( = Ro 09-0198) reported by Wakamiya et al.3). Weconsidered that this problem had arisen from the difficulty in discriminating the amino acid residue as Ala or Phe in the sequence analysis using NMR. Therefore, we employed both NMRarid Edmandegradation methods to analyze the structure of 1. The discrimination of the Phe residue from the Ala residue was possible with Edmandegradation, and the sulfide bridges in the lanthionine (Lan) and methyllanthionine (MeLan) moiety and the NHbridge in the lysinoalanine (LysAla) moiety were easily determined by analyzing the NOESYspectra. As PA48009 (1) was identified as duramycin1'2) by physical measurements, wereport here the revised structure of duramycin (1) as shownin Fig. 1.

99mTc-Labeled Duramycin as a Novel Phosphatidylethanolamine-Binding Molecular Probe

“…By including TPPTS in the coordination chemistry, 99m Tc-duramycin remains stable both in solution and in vivo, consistent with the prior findings (17,18). The second key factor that contributes to the stability of 99m Tc-duramycin stems from the structural configuration of duramycin, in which the polypeptide is stabilized by 3 internal thioether bridges (7,8). In addition, the absence of a free peptidergic terminus as a result of the circularization of the polypeptide minimizes the chance of proteolytic degradation by blood-borne proteases and peptidases (7,8).…”

“…The overall structure of duramycin assumes a compact cyclic configuration, with a single binding pocket that specifically interacts with PtdE (7,8). Stabilized by 3 internal thioether linkages, duramycin is the smallest known polypeptide that has a defined 3-dimensional binding site (7,8). The binding pocket of duramycin resembles a gloveshaped surface that fits around the PtdE head group with well-defined physicochemical interactions.…”

“…Duramycin binds the head group of PtdE with high affinity at a molar ratio of 1:1 (9)(10)(11). The overall structure of duramycin assumes a compact cyclic configuration, with a single binding pocket that specifically interacts with PtdE (7,8). Stabilized by 3 internal thioether linkages, duramycin is the smallest known polypeptide that has a defined 3-dimensional binding site (7,8).…”

“…As a potential molecular probe candidate for PtdE, duramycin is a 19-amino acid peptide produced by Streptoverticillium cinnamoneus (7,8). Duramycin binds the head group of PtdE with high affinity at a molar ratio of 1:1 (9)(10)(11).…”

Duramycin-porphyrin conjugates for targeting of tumour cells using photodynamic therapy

“…The presence of the covalent linkages also results in duramycin's stable binding site which selectively recognises the membrane phos-pholipid phosphatidylethanolamine (PE) through binding to its polar head group [4]. Duramycin binds to PE with high specificity with a binding molar ratio of 1:1 and a dissociation constant in the low nanomolar range [5]. The lantibiotic cinnamycin, which is structurally similar to duramycin, was shown to induce non-specific transbilayer membrane movement of phospholipids in model and cell membranes [6].…”