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ABSTRACT: Azotobacter vinelandii strain ATCC 12837 produces peptide siderophores of the general class known as pyoverdines. In the past, it was assumed that a single well-defined pyoverdine was produced by each parent microorganism. However, there are a number of reports of incompletely characterized pyoverdines that demonstrate heterogeneity in pyoverdine preparations obtained from a single organism, but the nature of this phenomena has not been explained. This study shows that A. vinelandii does indeed produce more than one pyoverdine and that these compounds differ in their peptide components. The metabolism of these siderophores suggests that only one of them is a true siderophore while the others are metabolic byproducts. It was demonstrated that this phenomenon is likely due to intrinsic limitations of the synthetase complex involved in the biosynthesis of these compounds. Characterization of two of the major pyoverdines produced demonstrated that they are novel compounds, although they belonged to the Azotobacter-type family of pyoverdines.
Biology of Metals 02/1991; 4(4):223-32.
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ABSTRACT: The siderophore produced by Azotobacter vinelandii strain UW belongs to a large family of peptidic siderophores collectively called pyoverdines. The biosynthesis of the peptidyl moiety of this siderophore was shown to involve activation of the constituent amino acids as their adenylates, as demonstrated by amino acid-dependent ATP-[32P]pyrophosphate exchange. The enzyme system responsible for this activation was partially purified by chromatographic techniques.
Biochimica et Biophysica Acta 04/1990; 1038(1):47-51. · 4.66 Impact Factor
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ABSTRACT: Electron microscopic examination has revealed the vesicular nature of the membrane component, of the cell-free system of Aerobacter aerogenes 62-1, which catalyses lysine: N6-hydroxylation. Regardless of the orientation of the vesicles, N-hydroxylation process is still stimulated by pyruvate. Both pyruvate oxidation and lysine: N6-hydroxylation were inhibited by protonophores and Gramicidin S.
Biochimica et Biophysica Acta 04/1989; 990(3):240-5. · 4.66 Impact Factor
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ABSTRACT: Electron microscopic examination has revealed the vesicular nature of the membrane component, of the cell-free system of Aerobacter aerogenes 62-1, which catalyses lysine: N6-hydroxylation. Regardless of the orientation of the vesicles, N-hydroxylation process is still stimulated by pyruvate. Both pyruvate oxidation and lysine: N6-hydroxylation were inhibited by protonophores and Gramicidin S.
Biochimica et Biophysica Acta (BBA) - General Subjects 990(3):240-245. · 5.00 Impact Factor
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ABSTRACT: N-Ethylmaleimide was found to inhibit both pyruvate oxidation and lysine: N6-hydroxylation catalyzed by an enzyme system derived from Aerobacter aerogenes 62-1. Studies of pyruvate utilization in the presence and absence of lysine indicated a 1:1 stoichiometric relationship between consumption of pyruvate and production of N6-hydroxylation. Similar studies with an Escherichia coli mutant enzyme system revealed a 2:1 stoichiometric relationship between the above-mentioned processes. The formation of a nitrone derivative by interaction of N6-hydroxylysine with pyruvate has been suggested to provide the basis for the consumption of an additional mole of pyruvate in the E. coli enzyme system. Phenylhydrazine and 6-diazo-5-oxo-l-norleucine, the former after standing for appropriate periods, have been found to inhibit lysine: N6-hydroxylation reaction. The implications of these observations to the mechanism(s) operative in lysine: N6-hydroxylation are discussed.
Bioorganic Chemistry. 17(1):13-27.
