1M6S

Crystal Structure Of Threonine Aldolase

1M6S の概要

• エントリーDOI: 10.2210/pdb1m6s/pdb
• 関連するPDBエントリー: 1LW4 1LW5
• 分子名称: L-allo-threonine aldolase, CALCIUM ION, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: pyridoxal phosphate, plp, vitamin b12, enzyme, threonine, lyase
• 由来する生物種: Thermotoga maritima
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 153568.15

構造登録者

Burley, S.K.,Kielkopf, C.L. (登録日: 2002-07-17, 公開日: 2002-12-11, 最終更新日: 2025-03-26)

主引用文献

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+

実験手法

X-RAY DIFFRACTION (1.8 Å)