CHARACTERIZATION OF SSDESB, AN N-HYDROXYLASE FROM STREPTOMYCES SVICEUS

 

Overview

 

Biocatalysts are promising green technologies used in the chemical industry with increasing commercial demand. Enzymes are powerful biocatalysts as they can quickly direct the selectivity of a chemical process, utilize lower temperatures, and be combined with other enzymes in one-pot reactions under nontoxic conditions. To find suitable biocatalysts, natural product biosynthetic enzymes are useful starting points, as they are involved in making structurally diverse, chiral molecules. Hydroxamate siderophores (e.g., desferrioxamine B) are natural products that use flavin-dependent NMOs (e.g., DesB) to synthesize hydroxylamines en route to producing hydroxamates for metal-chelation. DesB N-hydroxylates various alkyl diamines to produce hydroxylamine products in a single step.

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Our overall objective is to characterize and expand the substrate scope of DesB from Streptomyces sviceus (SsDesB) to engineer it into a biocatalyst. This enzyme catalyzes the first committed step in the biosynthesis of the lysine-derived siderophore desferrioxamine B, a clinically used drug used to treat pathological iron deposition. Using kinetic and structural studies (in collaboration with George Lountos at the National Cancer Institute) on DesB, we aim to understand its enzymatic mechanism. We hope that characterizing this enzyme will allow us to synthesize diverse hydroxylamines as well as identify and characterize other homologs from metal polluted environments.

 

 

 

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