UK-69,753, a novel member of the efrotomycin family of antibiotics. II. Structure determination and biological activity.

Abstract

A novel antibiotic, UK-69,753, has been isolated from a submerged fermentation of Amycolatopsis orientalis strain N731-15. UK-69,753 has been assigned the structure 1 using spectroscopic means, primarily by NMRanalysis. UK-69,753is a glycoside of factumycin (A40A), a previously reported member of a small groupof antibiotics related to aurodoxand efrotomycin. UK-69,753wasshownto have potent activity both in vitro and in vivo against the swine pathogen Treponemahyodysenteriae.In the preceding paper1}, we have described the taxonomy, fermentation and isolation of UK-69,753 (1), a novel memberof the efrotomycin2) family of antibiotics. In this paper we describe the structure elucidation of UK-69,753 along with its antibacterial activity. Results and DiscussionStructure Determination of UK-69,753 The structure of UK-69,753 (1) has been determined by spectroscopic means, relying heavily on the results ofNMRanalysis.^H, 13C, carbon multiplicity (distortionless enhancement by polarization transfer: DEPT)3) and 2D (homonuclear correlation: COSY4) and heteronuclear correlation: HETCOR5)) NMR spectra were recorded on UK-69,753in CD3OD, and the results of these experiments are summarizedin Table 1. The 13C NMRspectrum showed 57 distinct resonances with one line at 130.41 ppm accounting for two carbons, indicating that UK-69,753 contains 58 carbon atoms. Using the data available primarily from the two correlation experiments, eight distinct spin systems comprising 47 carbons were identified which correspond to the molecular fragments 2 through 9. The olefmic proton resonances of fragments 2, 7, and 8 were unambiguously assigned and measurement of the vicinal coupling constants of these resonances in the 1H NMRspectrum at 500 MHz (Fig. 1) allowed for assignment of the configuration of each disubstituted olefin in these fragments. The configuration of the two trisubstituted olefins (fragments 7 and 8) were both assigned as drawn on the basis of nuclear Overhauser effect (NOE) experiments1. The carbonyl and quaternary olefinic carbons in fragments 7 and 8 were assigned via multiple bond heteronuclear correlation (MBHC)to nearby carbons bearing protons.Consideration of the part structures 2~9 assembled from an analysis of NMRdata lead to the hypothesis that UK-69,753 is a novel memberof a small group of antibiotics characterized by compoundsThe nuclear Overhauser polarizations, observed at 500 MHz,were consistently negative.

Discovery of Efrotomycin Congeners and Heterologous Expression-Based Insights into the Self-Resistance Mechanism

“…The chair conformation of the pyran moiety (from C-28 to C-32) with the axial H-30 and H-32 and the equatorial H-29 was supported by the small coupling constant of 3 J H-29,H-30 (3.5 Hz) and the ROESY correlation between H-30/H-32 (Figure 1, Table S1). The disaccharide unit (sugars A and B) in 1 has highly similar NMR data to those in UK-69,753 17 (Table S2) and was assigned to be 6-deoxy-4-O-(6-deoxy-2-O-methyl-α-L-mannose)-3-O-methyl-β-D-allose (Figure 1). The linkage of C-30−O−C-1′ between the disaccharide and the aglycone was established by the HMBC correlation from H-30 to C-1′ (Figure 1).…”

“…Analysis of the 1 H, 13 C, and HSQC NMR data of 1 (Table S1) revealed high structure similarity of 1 and UK-69,753 (Table S2), a member of the elfamycin family of antibiotics isolated from Amycolatopsis orientalis N731-15. 17 The major difference was the presence of an additional hydroxy group at C-29 in 1, which was supported by the deshielded shift by 32.5 ppm at C-29 (δ C 70.7) in 1 compared to that of UK-69,753 (Table S2). 17 Thus, the planar structure of 1 was determined (Figure 1).…”

“…The major difference was the presence of an additional hydroxy group at C-29 in 1 , which was supported by the deshielded shift by 32.5 ppm at C-29 (δ C 70.7) in 1 compared to that of UK-69,753 (Table S2). Thus, the planar structure of 1 was determined (Figure ).…”

Looking Back to Amycolatopsis: History of the Antibiotic Discovery and Future Prospects

“…Strong antimicrobial activity in vitro and in vivo against the swine Gram-negative anaerobic pathogen Treponema hyodysenteriae [95,96] MM 47761 and MM 4972; MM 55266, and MM 55268 Antimicrobial activity against Gram-positive bacteria [97,98] Eremomycin B Antimicrobial activity against Gram-positive bacteria [99][100][101] Orienticins A-D Antimicrobial activity against S. aureus (including MRSA) [102] Chloroorienticins A-E Antimicrobial activity against S. aureus (including MRSA) [103] LY264826 Antimicrobial activity against Gram-positive bacteria (including MRSA) [104] ECO-0501 Strong antimicrobial activity against Gram-positive bacteria (including MRSA and VRE) [28] A. palatopharyngis Antibiotic biosynthetic genes were identified [27] A. regifaucium Kigamicins A-E Antimicrobial activity against Gram-positive bacteria (including MRSA); Kigamicin D is an anticancer agent [48,[105][106][107] A. rifamycinica Tetracenomycin Х…”