1M6S
Crystal Structure Of Threonine Aldolase
Summary for 1M6S
| Entry DOI | 10.2210/pdb1m6s/pdb |
| Related | 1LW4 1LW5 |
| Descriptor | L-allo-threonine aldolase, CALCIUM ION, CHLORIDE ION, ... (4 entities in total) |
| Functional Keywords | pyridoxal phosphate, plp, vitamin b12, enzyme, threonine, lyase |
| Biological source | Thermotoga maritima |
| Total number of polymer chains | 4 |
| Total formula weight | 153568.15 |
| Authors | Burley, S.K.,Kielkopf, C.L. (deposition date: 2002-07-17, 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 Cited by 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: 12269813DOI: 10.1021/bi020393+ PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.8 Å) |
Structure validation
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