5BYV

Crystal structure of MSM-13, a putative T1-like thiolase from Mycobacterium smegmatis

5BYV の概要

• エントリーDOI: 10.2210/pdb5byv/pdb
• 関連するPDBエントリー: 5BZ4
• 分子名称: Beta-ketothiolase (2 entities in total)
• 機能のキーワード: thiolase, mycobacterium smegmatis, t1-like, tetrameric, transferase
• 由来する生物種: Mycobacterium smegmatis str. MC2 155
• タンパク質・核酸の鎖数: 12
• 化学式量合計: 516093.89

構造登録者

Janardan, N.,Harijan, R.K.,Keima, T.R.,Wierenga, R.,Murthy, M.R.N. (登録日: 2015-06-11, 公開日: 2016-05-18, 最終更新日: 2023-11-08)

主引用文献

Janardan, N.,Harijan, R.K.,Kiema, T.R.,Wierenga, R.K.,Murthy, M.R.
Structural characterization of a mitochondrial 3-ketoacyl-CoA (T1)-like thiolase from Mycobacterium smegmatis
Acta Crystallogr.,Sect.D, 71:2479-2493, 2015

PubMed Abstract: Thiolases catalyze the degradation and synthesis of 3-ketoacyl-CoA molecules. Here, the crystal structures of a T1-like thiolase (MSM-13 thiolase) from Mycobacterium smegmatis in apo and liganded forms are described. Systematic comparisons of six crystallographically independent unliganded MSM-13 thiolase tetramers (dimers of tight dimers) from three different crystal forms revealed that the two tight dimers are connected to a rigid tetramerization domain via flexible hinge regions, generating an asymmetric tetramer. In the liganded structure, CoA is bound to those subunits that are rotated towards the tip of the tetramerization loop of the opposing dimer, suggesting that this loop is important for substrate binding. The hinge regions responsible for this rotation occur near Val123 and Arg149. The Lα1-covering loop-Lα2 region, together with the Nβ2-Nα2 loop of the adjacent subunit, defines a specificity pocket that is larger and more polar than those of other tetrameric thiolases, suggesting that MSM-13 thiolase has a distinct substrate specificity. Consistent with this finding, only residual activity was detected with acetoacetyl-CoA as the substrate in the degradative direction. No activity was observed with acetyl-CoA in the synthetic direction. Structural comparisons with other well characterized thiolases suggest that MSM-13 thiolase is probably a degradative thiolase that is specific for 3-ketoacyl-CoA molecules with polar, bulky acyl chains.

PubMed: 26627655
DOI: 10.1107/S1399004715019331

実験手法

X-RAY DIFFRACTION (2.162 Å)