1lw4

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spinqualitylabelsall models 1lw4, resolution 1.9Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

X-ray structure of L-Threonine Aldolase (low-specificity) in complex with L-allo-threonine

Overview

L-Threonine acetaldehyde-lyase (threonine aldolase, TA) is a, pyridoxal-5'-phosphate-dependent (PLP) enzyme that catalyzes conversion of, L-threonine or L-allo-threonine to glycine and acetaldehyde in a secondary, glycine biosynthetic pathway. X-ray structures of Thermatoga maritima TA, have been determined as the apo-enzyme at 1.8 A resolution and bound to, substrate L-allo-threonine and product glycine at 1.9 and 2.0 A, resolution, respectively. Despite low pairwise sequence identities, TA is, a member of aspartate aminotransferase (AATase) fold family of PLP, enzymes. The enzyme forms a 222 homotetramer with the PLP cofactor bound, via a Schiff-base linkage to Lys199 within a domain interface. The, structure reveals bound calcium and chloride ions that appear to, contribute to catalysis and oligomerization, respectively. Although, L-threonine and L-allo-threonine are substrates for T. maritima TA, enzymatic assays revealed a strong preference for L-allo-threonine., Structures of the external aldimines with substrate/product reveal a pair, of histidines that may provide flexibility in substrate recognition., Variation in the threonine binding pocket may explain preferences for, L-allo-threonine versus L-threonine among TA family members.

About this Structure

1LW4 is a Single protein structure of sequence from Thermotoga maritima with CA, CL, TLP and PLP as ligands. Active as Threonine aldolase, with EC number 4.1.2.5 Full crystallographic information is available from OCA.

Reference

X-ray structures of threonine aldolase complexes: structural basis of substrate recognition., Kielkopf CL, Burley SK, Biochemistry. 2002 Oct 1;41(39):11711-20. PMID:12269813

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