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Biosci Rep. 2018 Oct 17;38(5). pii: BSR20181605. doi: 10.1042/BSR20181605. Print 2018 Oct 31.

Structural and functional characterisation of the entry point to pyocyanin biosynthesis in Pseudomonas aeruginosa defines a new 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase subclass.

Author information

1
Biomolecular Interaction Centre and School of Physical and Chemical Sciences, University of Canterbury, Christchurch 8041, New Zealand.
2
Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland 1142, New Zealand.
3
SAXS/WAXS, Australian Synchrotron/ANSTO, 800 Blackburn Road, Clayton, VIC 3168, Australia.
4
Department of Chemistry and Biochemistry, University of Lethbridge, Alberta T1K 3M4, Canada.
5
Biomolecular Interaction Centre and School of Physical and Chemical Sciences, University of Canterbury, Christchurch 8041, New Zealand emily.parker@vuw.ac.nz g.b.jameson@massey.ac.nz.
6
Institute of Fundamental Sciences and the Riddet Institute, Massey University, Palmerston North 4442, New Zealand.
7
Ferrier Research Institute, Victoria University of Wellington, Wellington 6140, New Zealand.

Abstract

In Pseudomonas aeruginosa (Pae), the shikimate pathway end product, chorismate, serves as the last common precursor for the biosynthesis of both primary aromatic metabolites, including phenylalanine, tyrosine and tryptophan, and secondary aromatic metabolites, including phenazine-1-carboxylic acid (PCA) and pyocyanin (PYO). The enzyme 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAH7PS) catalyses the first committed step of the shikimate pathway, en route to chorismate. P. aeruginosa expresses multiple, distinct DAH7PSs that are associated with either primary or secondary aromatic compound biosynthesis. Here we report the structure of a type II DAH7PS, encoded by phzC as part of the duplicated phenazine biosynthetic cluster, from P. aeruginosa (PAO1) revealing for the first time the structure of a type II DAH7PS involved in secondary metabolism. The omission of the structural elements α2a and α2b, relative to other characterised type II DAH7PSs, leads to the formation of an alternative, dimeric, solution-state structure for this type II DAH7PS with an oligomeric interface that has not previously been characterised and that does not facilitate the formation of aromatic amino acid allosteric binding sites. The sequence similarity and, in particular, the common N-terminal extension suggest a common origin for the type II DAH7PSs from P. aeruginosa. The results described in the present study support an expanded classification of the type II DAH7PSs as type IIA and type IIB based on sequence characteristics, structure and function of the resultant proteins, and on defined physiological roles within primary or secondary metabolism.

KEYWORDS:

DAHP synthase; aromatic amino acid; pyocyanin; shikimate

PMID:
30242059
PMCID:
PMC6435475
DOI:
10.1042/BSR20181605
[Indexed for MEDLINE]
Free PMC Article

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