Abstract
β-Hydroxy-α-amino acids (βH-AAs) are key components of many bioactive molecules as well as exist as specialised metabolites. Among these βH-AAs, 4-fluorothreonine (4-FT) is the only naturally occurring fluorinated AA discovered thus far. Here we report overexpression and biochemical characterisation of 4-fluorothreonine transaldolase from Streptomyces sp. MA37 (FTaseMA), a homologue of FTase previously identified in the biosynthesis of 4-FT in S. cattleya. FTaseMA displays considerable substrate plasticity to generate 4-FT as well as other β-hydroxy-α-amino acids with various functionalities at C4 position, giving the prospect of new chemo-enzymatic applications. The enzyme has a hybrid of two catalytic domains, serine hydroxymethyltransferase (S) and aldolase (A). Site-directed mutagenesis allowed the identification of the key residues of FTases, suggesting that the active site of A domain has a historical reminiscent feature in metal-dependent aldolases. Elemental analysis demonstrated that FTaseMA is indeed a Zn2+-dependent enzyme, the first example of pyridoxal phosphate (PLP) enzyme family fused with a metal-binding domain carrying out a distinct catalytic role. Finally, FTaseMA showed divergent evolutionary origin with other PLP dependent enzymes.
Original language | English |
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Pages (from-to) | 3885-3896 |
Number of pages | 12 |
Journal | Applied Microbiology and Biotechnology |
Volume | 104 |
Early online date | 6 Mar 2020 |
DOIs | |
Publication status | Published - 1 May 2020 |
Bibliographical note
Open Access via the Springer Compact Agreement.This study was funded by IBioIC PhD studentship (LW), Leverhulme Trust Research Project (HD and MHT, project No. RPG-2014-418), The Elphinstone Scholarship of University of Aberdeen (QF), Leverhulme Trust-Royal Society Africa award (KK and HD, AA090088) and the jointly funded UK Medical Research Council – UK Department for International Development (MRC/DFID) Concordat agreement African Research Leaders Award (KK and HD, MR/S00520X/1), Biotechnology and Biological Sciences Research Council UK (HD and SW, BB/P00380X/1) and National Natural Science Foundation of China (31,570,033, 31,811,530,299, and 31,870,035 to YY), and the Royal Society-NSFC Newton Mobility Grant Award (IEC\NSFC\170,617 to HD and YY).
Keywords
- beta-Hydroxy-alpha-amino acids
- 4-fluorothreonine
- 4-fluorothreonine transaldolase
- Transaldolation
- Streptomyces sp