A β-alanine catabolism pathway containing a highly promiscuous ω-transaminase in the 12-aminododecanate-degrading Pseudomonas sp. strain AAC

Matthew Wilding, Thomas S. Peat, Janet Newman, Colin Scott*

*Corresponding author for this work

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We previously isolated the transaminase KES23458 from Pseudomonas sp. strain AAC as a promising biocatalyst for the production of 12-aminododecanoic acid, a constituent building block of nylon-12. Here, we report the subsequent characterization of this transaminase. It exhibits activity with a broad substrate range which includes α-, β-, and ω-amino acids, as well as α,ω-diamines and a number of other industrially relevant compounds. It is therefore a prospective candidate for the biosynthesis of a range of polyamide monomers. The crystal structure of KES23458 revealed that the protein forms a dimer containing a large active site pocket and unusual phosphorylated histidine residues. To infer the physiological role of the transaminase, we expressed, purified, and characterized a dehydrogenase from the same operon, KES23460. Unlike the transaminase, the dehydrogenase was shown to be quite selective, catalyzing the oxidation of malonic acid semialdehyde, formed from β-alanine transamination via KES23458. In keeping with previous reports, the dehydrogenase was shown to catalyze both a coenzyme A (CoA)-dependent reaction to form acetyl-CoA and a significantly slower CoA-independent reaction to form acetate. These findings support the original functional assignment of KES23458 as a β-alanine transaminase. However, a seemingly well-adapted active site and promiscuity toward unnatural compounds, such as 12-aminododecanoic acid, suggest that this enzyme could perform multiple functions for Pseudomonas sp. strain AAC.

Original languageEnglish
Pages (from-to)3846-3856
Number of pages11
JournalApplied and Environmental Microbiology
Volume82
Issue number13
DOIs
Publication statusPublished - Jul 2016
Externally publishedYes

Fingerprint Dive into the research topics of 'A β-alanine catabolism pathway containing a highly promiscuous ω-transaminase in the 12-aminododecanate-degrading Pseudomonas sp. strain AAC'. Together they form a unique fingerprint.

Cite this