Investigation of phosphonate biosynthesis: I. Structure of dehydrophos II. Mechanism of hydroxyethylphosphonate dioxygenase

Whitteck, John T.

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https://hdl.handle.net/2142/17023 Copy

Description

Title

Investigation of phosphonate biosynthesis: I. Structure of dehydrophos II. Mechanism of hydroxyethylphosphonate dioxygenase

Author(s)

Whitteck, John T.

Issue Date

2010-08-31T20:29:38Z

Director of Research (if dissertation) or Advisor (if thesis)

van der Donk, Wilfred A.

Doctoral Committee Chair(s)

van der Donk, Wilfred A.

Committee Member(s)

• Katzenellenbogen, John A.
• Burke, Martin D.
• Metcalf, William W.

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• biosynthesis
• phosphonate
• dehydrophos
• phosphinothricin
• hydroxyethylphosphonate dioxygenase

Abstract

Natural product phosphonates are used extensively in the clinic as antibacterials and in commercial agriculture as herbicides. In an effort to efficiently discover new natural product phosphonates, a multidisciplinary, collaborative program has been established at the Institute for Genomic Biology at the University of Illinois at Urbana-Champaign to mine genomes for novel phosphonate structures and biosynthetic enzymes. Detailed herein are my contributions to this effort through assigning the structure of dehydrophos and through investigations into the mechanism of hydroxyethylphosphonate dioxygenase. Dehydrophos was discovered as a secondary metabolite of Streptomyces luridus and was shown to have broad spectrum activity against both Gram-negative and Gram-positive bacteria. Chemical synthesis of the originally proposed structure showed it to be inconsistent with the isolated material. Labeling studies with extensive NMR spectroscopic analysis led to reassignment of the structure as a tripeptide containing an aminophosphonate analogue of dehydroalanine. This structure was confirmed through organic synthesis. Hydroxyethylphosphonate dioxygenase (HEPD) catalyzes a biochemically unprecedented carbon-carbon bond cleavage reaction as part of the early steps of phosphinothricin biosynthesis. Characterization of HEPD has shown it to be a non-heme iron dependent dioxygenase that is dependent on only ferrous iron and molecular oxygen for activity. Studies with substrate isotopologues and substrate analogues have given insight into the mechanism and suggest a hydroperoxylation mechanism for the early steps.

Graduation Semester

2010-08

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http://hdl.handle.net/2142/17023

Copyright and License Information

Copyright 2010 John T. Whitteck

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