1LW5

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

Summary for 1LW5

• Entry DOI: 10.2210/pdb1lw5/pdb
• Related: 1LW4 1M6S
• Descriptor: L-allo-threonine aldolase, CALCIUM ION, CHLORIDE ION, ... (6 entities in total)
• Functional Keywords: pyridoxal-5-phosphate, plp, enzyme, product complex, threonine, structural genomics, psi, protein structure initiative, new york sgx research center for structural genomics, nysgxrc, lyase
• Biological source: Thermotoga maritima
• Total number of polymer chains: 4
• Total formula weight: 157360.03

Authors

Kielkopf, C.L.,Burley, S.K.,New York SGX Research Center for Structural Genomics (NYSGXRC) (deposition date: 2002-05-30, release date: 2002-12-11, Last modification date: 2025-03-26)

Primary citation

Kielkopf, C.L.,Burley, S.K.
X-ray Structures of Threonine Aldolase Complexes: Structural Basis of Substrate Recognition
Biochemistry, 41:11711-11720, 2002

PubMed Abstract: 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.

PubMed: 12269813
DOI: 10.1021/bi020393+

Experimental method

X-RAY DIFFRACTION (2.05 Å)