In:
Acta Crystallographica Section D Biological Crystallography, International Union of Crystallography (IUCr), Vol. 70, No. 6 ( 2014-06-01), p. 1695-1703
Abstract:
L- allo -Threonine aldolase (LATA), a pyridoxal-5′-phosphate-dependent enzyme from Aeromonas jandaei DK-39, stereospecifically catalyzes the reversible interconversion of L- allo -threonine to glycine and acetaldehyde. Here, the crystal structures of LATA and its mutant LATA_H128Y/S292R were determined at 2.59 and 2.50 Å resolution, respectively. Their structures implied that conformational changes in the loop consisting of residues Ala123–Pro131, where His128 moved 4.2 Å outwards from the active site on mutation to a tyrosine residue, regulate the substrate specificity for L- allo -threonine versus L-threonine. Saturation mutagenesis of His128 led to diverse stereoselectivity towards L- allo -threonine and L-threonine. Moreover, the H128Y mutant showed the highest activity towards the two substrates, with an 8.4-fold increase towards L-threonine and a 2.0-fold increase towards L- allo -threonine compared with the wild-type enzyme. The crystal structures of LATA and its mutant LATA_H128Y/S292R reported here will provide further insights into the regulation of the stereoselectivity of threonine aldolases targeted for the catalysis of L- allo -threonine/L-threonine synthesis.
Type of Medium:
Online Resource
ISSN:
1399-0047
DOI:
10.1107/S1399004714007664
DOI:
10.1107/S1399004714007664/mh5119sup1.pdf
Language:
Unknown
Publisher:
International Union of Crystallography (IUCr)
Publication Date:
2014
detail.hit.zdb_id:
2020492-9
detail.hit.zdb_id:
2968623-4
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