The Siderophore Synthetase IucA of the Aerobactin Biosynthetic Pathway Uses an Ordered Mechanism.
Biochemistry
; 59(23): 2143-2153, 2020 06 16.
Article
em En
| MEDLINE
| ID: mdl-32432457
ABSTRACT
Biosynthesis of the hydroxamate siderophore aerobactin requires the activity of four proteins encoded within the iuc operon. Recently, we biochemically reconstituted the biosynthetic pathway and structurally characterized IucA and IucC, two enzymes that sequentially couple N6-acetyl-N6-hydroxylysine to the primary carboxylates of citrate. IucA and IucC are members of a family of non-ribosomal peptide synthetase-independent siderophore (NIS) synthetases that are involved in the production of other siderophores, including desferrioxamine, achromobactin, and petrobactin. While structures of several members of this family were solved previously, there is limited mechanistic insight into the reaction catalyzed by NIS synthetases. Therefore, we performed a terreactant steady-state kinetic analysis and herein provide evidence for an ordered mechanism in which the chemistry is preceded by the formation of the quaternary complex. We further probed two regions of the active site with site-directed mutagenesis and identified several residues, including a conserved motif that is present on a dynamic loop, that are important for substrate binding and catalysis.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
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Vias Biossintéticas
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Ácidos Hidroxâmicos
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Oxo-Ácido-Liases
Idioma:
En
Revista:
Biochemistry
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Estados Unidos