Complexes of mycobactin from Mycobacterium smegmatis with scandium, yttrium and lanthanum

The interaction of cations of group IIIb elements (Sc, Y, La) with mycobactin S in ethanol leads to the formation of 1:1 complexes which closely resemble the known aluminium compound with respect to ultraviolet absorption and fluorescence emission spectra. Determination of molar stoichiometry by spe...

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Bibliographic Details
Published in:Biology of metals 1991-01, Vol.4 (4), p.207-210
Main Authors: ANDRES, Y, MACCORDICK, H. J, HUBERT, J.-C
Format: Article
Language:English
Subjects:
Biological and medical sciences
Chemical Physics
Fundamental and applied biological sciences. Psychology
Kinetics
Lanthanum - metabolism
Microbiology
Models, Molecular
Mycobacterium - metabolism
Mycology
Oxazoles - metabolism
Physics
Scandium - metabolism
Spectrometry, Fluorescence
Spectrum Analysis
Yttrium - metabolism
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Summary:The interaction of cations of group IIIb elements (Sc, Y, La) with mycobactin S in ethanol leads to the formation of 1:1 complexes which closely resemble the known aluminium compound with respect to ultraviolet absorption and fluorescence emission spectra. Determination of molar stoichiometry by spectrophotometry shows that this method can be conveniently applied to the estimation of purity in mycobactin samples. Hydrolytic dissociation measurements based on aqueous extraction of the labelled complexes in heterogeneous phase indicate a pronounced gradation in cation-binding stability, which increases from La (rapid and complete dissociation) to sc (approximately 24% dissociation under similar conditions). The observed properties of the complexes are rationalized by semi-empirical model calculations, which suggest that ionic radius effects resulting from interaction of the IIIb cations with mycobactin S would not favour octahedral coordination of these elements as in the stable Fe(III) complex.
ISSN:0933-5854
0966-0844
1572-8773
DOI:10.1007/BF01141182