ジャーナル: J Bacteriol / 年: 2014 タイトル: ε, a new subunit of RNA polymerase found in gram-positive bacteria. 著者: Andrew N Keller / Xiao Yang / Jana Wiedermannová / Olivier Delumeau / Libor Krásný / Peter J Lewis / 要旨: RNA polymerase in bacteria is a multisubunit protein complex that is essential for gene expression. We have identified a new subunit of RNA polymerase present in the high-A+T Firmicutes phylum of ...RNA polymerase in bacteria is a multisubunit protein complex that is essential for gene expression. We have identified a new subunit of RNA polymerase present in the high-A+T Firmicutes phylum of Gram-positive bacteria and have named it ε. Previously ε had been identified as a small protein (ω1) that copurified with RNA polymerase. We have solved the structure of ε by X-ray crystallography and show that it is not an ω subunit. Rather, ε bears remarkable similarity to the Gp2 family of phage proteins involved in the inhibition of host cell transcription following infection. Deletion of ε shows no phenotype and has no effect on the transcriptional profile of the cell. Determination of the location of ε within the assembly of RNA polymerase core by single-particle analysis suggests that it binds toward the downstream side of the DNA binding cleft. Due to the structural similarity of ε with Gp2 and the fact they bind similar regions of RNA polymerase, we hypothesize that ε may serve a role in protection from phage infection.
構造決定の手法: 多波長異常分散 / 解像度: 2.3→23.065 Å / SU ML: 0.31 / σ(F): 1.34 / 位相誤差: 32.28 / 立体化学のターゲット値: ML 詳細: SF FILE CONTAINS FRIEDEL PAIRS UNDER I/F_MINUS AND I/F_PLUS COLUMNS.
Rfactor
反射数
%反射
Selection details
Rfree
0.2561
1125
5.22 %
RANDOM
Rwork
0.2135
-
-
-
obs
0.2158
19734
99.45 %
-
溶媒の処理
減衰半径: 0.9 Å / VDWプローブ半径: 1.11 Å / 溶媒モデル: FLAT BULK SOLVENT MODEL
精密化ステップ
サイクル: LAST / 解像度: 2.3→23.065 Å
タンパク質
核酸
リガンド
溶媒
全体
原子数
3505
0
0
37
3542
拘束条件
Refine-ID
タイプ
Dev ideal
数
X-RAY DIFFRACTION
f_bond_d
0.004
3572
X-RAY DIFFRACTION
f_angle_d
0.715
4779
X-RAY DIFFRACTION
f_dihedral_angle_d
13.159
1414
X-RAY DIFFRACTION
f_chiral_restr
0.027
489
X-RAY DIFFRACTION
f_plane_restr
0.003
621
LS精密化 シェル
Refine-ID: X-RAY DIFFRACTION / Total num. of bins used: 16