A 20-residue peptide of the inner membrane protein OutC mediates interaction with two distinct sites of the outer membrane secretin OutD and is essential for the functional type II secretion system in Erwinia chrysanthemi.
A 20-residue peptide of the inner membrane protein OutC mediates interaction with two distinct sites of the outer membrane secretin OutD and is essential for the functional type II secretion system in Erwinia chrysanthemi.
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内膜蛋白 OutC 的 20 个残基肽介导与外膜促胰液素 OutD 的两个不同位点的相互作用，对于菊欧文氏菌的功能性 II 型分泌系统至关重要。
DOI：
10.1111/j.1365-2958.2010.07149.x
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发表时间：
2010
影响因子：
3.6
通讯作者：
Login FH
中科院分区：
文献类型：
--
作者：
Login FH
II 型分泌系统 (T2SS) 被变形菌广泛利用来分泌参与细菌生存和发病机制的酶和毒素。由促胰液素OutD和内膜蛋白OutC形成的外膜孔是分泌复合物的两个关键成分，参与分泌特异性。在这里，我们表明 OutC 和 OutD 的周质区域直接相互作用，并将 OutC 的相互作用位点映射到名为 OutCsip 的 20 个残基肽（分泌素相互作用肽，残基 139-158）。该肽在体外与 OutD 周质区域的两个不同位点相互作用，一个位于 N0 子结构域，另一个与 N2-N3' 子结构域重叠。 OutD 的两个相互作用位点与 OutCsip 的结合方式不同。位于 OutCsip 内的单一取代 V143S 可防止其与 OutD 的两个结合位点之一相互作用，并完全失活 T2SS。我们发现 OutD 的 N0 子结构域还与位于跨膜片段附近区域的 OutC 内的第二个结合位点相互作用。我们认为 OutC 和 OutD 这些不同区域之间的连续相互作用可能在切换分泌机器方面具有重要的功能。
The type II secretion system (T2SS) is widely exploited by proteobacteria to secrete enzymes and toxins involved in bacterial survival and pathogenesis. The outer membrane pore formed by the secretin OutD and the inner membrane protein OutC are two key components of the secretion complex, involved in secretion specificity. Here, we show that the periplasmic regions of OutC and OutD interact directly and map the interaction site of OutC to a 20‐residue peptide named OutCsip (secretininteractingpeptide, residues 139–158). This peptide interactsin vitrowith two distinct sites of the periplasmic region of OutD, one located on the N0 subdomain and another overlapping the N2‐N3′ subdomains. The two interaction sites of OutD have different modes of binding to OutCsip. A single substitution, V143S, located within OutCsip prevents its interaction with one of the two binding sites of OutD and fully inactivates the T2SS. We show that the N0 subdomain of OutD interacts also with a second binding site within OutC located in the region proximal to the transmembrane segment. We suggest that successive interactions between these distinct regions of OutC and OutD may have functional importance in switching the secretion machine.