Metal complexes of sporidesmin D and dimethylgliotoxin, investigated by electrospray ionisation mass spectrometry.
Electrospray ionisation mass spectrometry (ES-MS) has been used to probe the coordination chemistry of metabolites such as sporidesmin D (spdD), found in the saprophytic fungus Pithomyces chartarum, and the related bisdethiobis(methylthio)gliotoxin (dimethylgliotoxin, Megtx). SpdD forms complexes of the type [spdD+M(MeCN)] and [2spdD+M]+ (M=Cu, Ag) and, at higher cone voltages, [spdD+M]+. The bis(ligand) ion [2spdD+M]+ was observed at very high cone voltages, indicating it has appreciable stability; the proposed structure of this species has a four-coordinate metal ion with two bidentate spdD ligands, coordinated through their SMe groups. 1H NMR titrations of spdD with K+, Ag+ and Cu+ provided additional evidence for complex formation with the soft metals. SpdD forms only relatively weak complexes with Zn2+, Cd2+, Co2+ and Mn2+, in keeping with the known reduced tendency of these metals to form stable thioether complexes. ES-MS studies of Megtx showed similar results to spdD, with stable adducts formed with Cu+ and Ag+ ions. The X-ray crystal structure of spdD is also reported.
Woodcock
J C
JC
Department of Chemistry, University of Waikato, Hamilton, New Zealand.
Henderson
W
W
Miles
C O
CO
Nicholson
B K
BK
D005912:Gliotoxin / Q000737:chemistry*; D007166:Immunosuppressive Agents / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization; D013173:Sporidesmins / Q000737:chemistry*
D007166:Immunosuppressive Agents; D008670:Metals; D013173:Sporidesmins; D005912:Gliotoxin; C001873:sporidesmin