6QMM

Crystal structure of Synecochoccus Spermidine Synthase in complex with putrescine, spermidine and MTA

6QMM の概要

• エントリーDOI: 10.2210/pdb6qmm/pdb
• 分子名称: Polyamine aminopropyltransferase, 1,4-DIAMINOBUTANE, SPERMIDINE, ... (7 entities in total)
• 機能のキーワード: synthase, homodimer, transferase
• 由来する生物種: Synechococcus elongatus (strain PCC 7942); 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 63696.61

構造登録者

Guedez, G.,Pothipongsa, A.,Incharoensakdi, A.,Salminen, T.A. (登録日: 2019-02-07, 公開日: 2019-03-27, 最終更新日: 2024-01-24)

主引用文献

Guedez, G.,Pothipongsa, A.,Siren, S.,Liljeblad, A.,Jantaro, S.,Incharoensakdi, A.,Salminen, T.A.
Crystal structure of dimericSynechococcusspermidine synthase with bound polyamine substrate and product.
Biochem.J., 476:1009-1020, 2019

PubMed Abstract: Spermidine is a ubiquitous polyamine synthesized by spermidine synthase (SPDS) from the substrates, putrescine and decarboxylated S-adenosylmethionine (dcAdoMet). SPDS is generally active as homodimer, but higher oligomerization states have been reported in SPDS from thermophiles, which are less specific to putrescine as the aminoacceptor substrate. Several crystal structures of SPDS have been solved with and without bound substrates and/or products as well as inhibitors. Here, we determined the crystal structure of SPDS from the cyanobacterium (SPDS) that is a homodimer, which we also observed in solution. Unlike crystal structures reported for bacterial and eukaryotic SPDS with bound ligands, SPDS structure has not only bound putrescine substrate taken from the expression host, but also spermidine product most probably as a result of an enzymatic reaction. Hence, to the best of our knowledge, this is the first structure reported with both amino ligands in the same structure. Interestingly, the gate-keeping loop is disordered in the putrescine-bound monomer while it is stabilized in the spermidine-bound monomer of the SPDS dimer. This confirms the gate-keeping loop as the key structural element that prepares the active site upon binding of dcAdoMet for the catalytic reaction of the amine donor and putrescine.

PubMed: 30877192
DOI: 10.1042/BCJ20180811

実験手法

X-RAY DIFFRACTION (2.18 Å)