1S5T

Crystal Structure Analysis of a mutant of DIHYDRODIPICOLINATE SYNTHASE--residue thr44 to val44

1S5T の概要

• エントリーDOI: 10.2210/pdb1s5t/pdb
• 関連するPDBエントリー: 1DHP 1S5V 1S5W
• 分子名称: Dihydrodipicolinate synthase (2 entities in total)
• 機能のキーワード: synthase, dihydrodipicolinate, lyase
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cytoplasm: P0A6L2
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 62605.93

構造登録者

Dobson, R.C.J.,Valegard, K.,Gerrard, J.A. (登録日: 2004-01-21, 公開日: 2004-04-27, 最終更新日: 2023-10-25)

主引用文献

Dobson, R.C.J.,Valegard, K.,Gerrard, J.A.
The Crystal Structure of Three Site-directed Mutants of Escherichia coli Dihydrodipicolinate Synthase: Further Evidence for a Catalytic Triad
J.MOL.BIOL., 338:329-339, 2004

PubMed Abstract: Dihydrodipicolinate synthase (DHDPS, EC 4.2.1.52) catalyses the branchpoint reaction of lysine biosynthesis in plants and microbes: the condensation of (S)-aspartate-beta-semialdehyde and pyruvate. The crystal structure of wild-type DHDPS has been published to 2.5A, revealing a tetrameric molecule comprised of four identical (beta/alpha)(8)-barrels, each containing one active site. Previous workers have hypothesised that the catalytic mechanism of the enzyme involves a catalytic triad of amino acid residues, Tyr133, Thr44 and Tyr107, which provide a proton shuttle to transport protons from the active site to solvent. We have tested this hypothesis using site-directed mutagenesis to produce three mutant enzymes: DHDPS-Y133F, DHDPS-T44V and DHDPS-Y107F. Each of these mutants has substantially reduced activity, consistent with the catalytic triad hypothesis. We have determined each mutant crystal structure to at least 2.35A resolution and compared the structures to the wild-type enzyme. All mutant enzymes crystallised in the same space group as the wild-type form and only minor differences in structure are observed. These results suggest that the catalytic triad is indeed in operation in wild-type DHDPS.

PubMed: 15066435
DOI: 10.1016/j.jmb.2004.02.060

実験手法

X-RAY DIFFRACTION (2.3 Å)