ジャーナル: Nat Struct Mol Biol / 年: 2014 タイトル: Structure of a pathogenic type 3 secretion system in action. 著者: Julia Radics / Lisa Königsmaier / Thomas C Marlovits / 要旨: Type 3 secretion systems use 3.5-megadalton syringe-like, membrane-embedded 'injectisomes', each containing an ~800-Å-long needle complex to connect intracellular compartments of infectious bacteria ...Type 3 secretion systems use 3.5-megadalton syringe-like, membrane-embedded 'injectisomes', each containing an ~800-Å-long needle complex to connect intracellular compartments of infectious bacteria and hosts. Here we identify requirements for substrate association with, transport through and exit from the injectisome of Salmonella enterica serovar Typhimurium. This guided the design of substrates that become trapped within the secretion path and enabled visualization of injectisomes in action in situ. We used cryo-EM to define the secretion path, providing a structural explanation as to why effector proteins must be unfolded during transport. Furthermore, trapping of a heterologous substrate in the needle prevents secretion of natural bacterial effectors. Together, the data reveal the path of protein secretion across multiple membranes and show that mechanisms rejecting unacceptable substrates can be undermined, and transport of bacterial effectors across an already assembled type 3 secretion system can be inhibited.
ダウンロード / ファイル: emd_2480.map.gz / 形式: CCP4 / 大きさ: 52.2 MB / タイプ: IMAGE STORED AS SIGNED BYTE
注釈
Tomogram of substrate trapped type-3 secretion systems from Salmonella typhimurium
ボクセルのサイズ
X=Y=Z: 19.88 Å
密度
最小 - 最大
-128.0 - 127.0
平均 (標準偏差)
-64.995986939999995 (±3.70534849)
対称性
空間群: 1
詳細
EMDB XML:
マップ形状
Axis order
X
Y
Z
Origin
-1
-302
47
サイズ
768
722
101
Spacing
768
722
101
セル
A: 14353.359 Å / B: 15267.84 Å / C: 2007.8799 Å α=β=γ: 90.0 °
CCP4マップ ヘッダ情報:
mode
envelope stored as signed bytes (from -128 lowest to 127 highest)
Å/pix. X/Y/Z
19.879998614958
19.88
19.88
M x/y/z
722
768
101
origin x/y/z
0.000
0.000
0.000
length x/y/z
14353.359
15267.840
2007.880
α/β/γ
90.000
90.000
90.000
start NX/NY/NZ
0
0
-40
NX/NY/NZ
55
55
81
MAP C/R/S
1
2
3
start NC/NR/NS
-302
-1
47
NC/NR/NS
722
768
101
D min/max/mean
-128.000
127.000
-64.996
-
添付データ
-
試料の構成要素
-
全体 : Type-3 secretion system from Salmonella typhimurium in situ (subs...
全体
名称: Type-3 secretion system from Salmonella typhimurium in situ (substrate trapped): Visualization of unfolded protein transport across membranes
要素
試料: Type-3 secretion system from Salmonella typhimurium in situ (substrate trapped): Visualization of unfolded protein transport across membranes
細胞器官・細胞要素: type 3 secretion system
-
超分子 #1000: Type-3 secretion system from Salmonella typhimurium in situ (subs...
超分子
名称: Type-3 secretion system from Salmonella typhimurium in situ (substrate trapped): Visualization of unfolded protein transport across membranes タイプ: sample / ID: 1000 / 集合状態: 1 / Number unique components: 1
分子量
理論値: 3.5 MDa
-
超分子 #1: type 3 secretion system
超分子
名称: type 3 secretion system / タイプ: organelle_or_cellular_component / ID: 1 / Name.synonym: injectisome / 組換発現: No / データベース: NCBI