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Correction to “Self-Assembly of Minimal Peptoid Sequences”
ACS Macro Letters ( IF 5.1 ) Pub Date : 2020-09-14 , DOI: 10.1021/acsmacrolett.0c00572
Valeria Castelletto , Jani Seitsonen , Kunal M. Tewari , Abshar Hasan , Robert M. Edkins , Janne Ruokolainen , Lalit M. Pandey , Ian W. Hamley , King Hang Aaron Lau

It has come to our attention that some of our cryo-electron microscopy (cryo-EM) images actually show ice contamination,(1) instead of the soft matter aggregates originally indicated in our publication. The images only relate to counterexample peptoid sequences that did not properly assemble (originally Figures 3D–K and S5E–G, I–M, and P). As such, our main finding of an ultrashort water-soluble tripeptoid assembling into ordered nanofibers is not changed. Our overall conclusions based on complementary cryo-EM, DLS, CAC, and fluorescence spectroscopy measurements are also unaffected. Nonetheless, the figures indicated and associated text require correction. In re-examining our cryo-EM data set, we found micrographs showing additional structures that are unlikely to be contaminants, which we previously took as less representative. Like the artifacts, the structures now identified are also irregular and consist of an ensemble of sizes centered around a mean. Incidentally, the mean sizes of these structures (50–250 nm in diameter, depending on sequence) fit better with our complementary DLS results—no agglomeration effect of individual 5–20 nm ice artifacts is needed anymore to reconcile the sizes measured by EM and DLS. The new Figure 3 and caption should be as shown on this page (main textual changes in bold). Figure 3. Cryo-TEM images from 2 wt % (20 mg/mL) solutions of N(FkF) (A–C), N(FKF) (D–F), N(KFF) (G–I), and N(kFF) (J–L). The left column shows zoomed in areas indicated in the center column. The right column shows additional typical images. Further areas are shown in Figure S5. The higher contrast smaller clusters in the upper left of panel K and far right of panel L may be ice contamination. Peptoid solutions were prepared in the same ways as for CAC measurements (see caption of Figure 2). See the Supporting Information for cryo-EM sample vitrification procedures. The corrections in the main text on page 496 (third page) are as follows (main changes in bold): In the bottom left paragraph below Figure 3, the corrected second sentence should read: “N(FKF), which has Nlys with the longer side chain in the same central residue position as N(FkF), formed globular assemblies ca. 50–250 nm wide (Figure 3D–F).” In the right column, the corrected first paragraph should read: “N(kFF) and N(KFF), which have the cationic Nae/Nlys placed at the N-terminus, also formed globular assemblies (Figure 3G–L). Upon closer inspection, N(KFF) actually assembled into ca. 100 nm spherical assemblies. N(kFF), which has the shorter Nae side chain, also formed 100 nm features (Figure 3J). However, this sequence appeared to exhibit stronger interactions, since some of the features instead coalesced into elongated structures ca. 100 nm in diameter (Figures 2J,K and S5P) as well as into nanosheets that spanned >100 nm (Figures 2L and S5O).” Also, in the right column, the corrected bottom paragraph should read: “Peptoid N(FKF) shows assemblies with RH centered around 108 nm (Figure 4B), which could indicate the larger assemblies (Figure 2D–F). N(kFF) and N(KFF) show mainly the presence of structures with RH centered around 0.5 and 44–49 nm (Figure 3C,D), corresponding respectively to monomers and the globules observed.” Lastly, in the Supporting Information, the corrected Figure S5 and caption should be as shown below (main textual changes in bold). Figure S5. Overview of cryo-TEM observations. The sequences N(FkF), N(FKF), N(KFF), and N(kFF) are arranged by row. All samples were prepared from 2 wt % (20 mg/mL) solutions. The two columns on the left are duplicated from Figure 3 of the main text, while the two columns on the right show additional areas. The imaged features include both typical some less often observed structures, including fiber bundles of N(FKF) in (H), and sheet-like structures for N(kFF) in (N and O) that span ca. 150 nm × 500 nm. Small amounts of higher contrast globular clusters with individual diameters <50 nm (A, lower right; D, lower left; M, upper left) are likely ice contamination.” This article references 1 other publications.

中文翻译:

对“最小类肽序列的自组装”的更正

引起我们注意的是,我们的某些冷冻电子显微镜(cryo-EM)图像实际上显示出冰污染,(1)而不是最初在我们的出版物中指出的软物质聚集体。图像仅与未正确组装的反例拟肽序列有关(最初是图3D–K和S5E–G,IM和P)。因此,我们对将超短水溶性三倍体类化合物组装成有序纳米纤维的主要发现没有改变。我们基于互补式冷冻-EM,DLS,CAC和荧光光谱测量的总体结论也不受影响。尽管如此,所显示的数字和相关文本仍需要更正。在重新检查我们的cryo-EM数据集时,我们发现了显微照片,这些照片显示了不太可能是污染物的其他结构,我们以前认为这些结构的代表性较低。像人工制品一样,现在识别出的结构也是不规则的,由以平均值为中心的大小合奏组成。顺便说一句,这些结构的平均尺寸(直径为50–250 nm,取决于序列)更适合我们的补充DLS结果-不再需要单个5–20 nm冰人工产物的团聚作用来协调EM和DLS。新的图3和标题应如本页所示(主要文字更改为加粗)。图3. N(FkF)(A–C),N(FKF)(D–F),N(KFF)(G–I)和2 wt%(20 mg / mL)溶液的低温TEM图像N(kFF)(J–L)。左列显示中心列中指示的区域。右列显示其他典型图像。其他区域如图S5所示。面板K左上角和面板L最右端的对比度较高的较小簇可能是冰污染。以与CAC测量相同的方式制备类肽溶液(请参见图2的标题)。有关冷冻EM样品玻璃化过程的信息,请参阅支持信息。在第496页(第三页)的正文中的更正如下(主要更改为粗体)):在图3下方的左下段中,更正后的第二句话应为:“ N(FKF),其Nlys的长侧链与N(FkF)处于相同的中央残基位置,形成球状组装体。50–250 nm宽(图3D–F)。” 在右栏中,更正后的第一段应为:“ N(kFF)和N(KFF),它们的阳离子Nae / Nlys位于N端,也形成了球状组件(图3G–L)。经仔细检查,N(KFF)实际上组装成大约2。100 nm球形组件。具有较短Nae侧链的N(kFF)也形成了100 nm的特征(图3J)。但是,此序列似乎表现出更强的相互作用,因为某些功能反而合并为细长结构长约 直径为100 nm(图2J,K和S5P)以及跨度大于100 nm的纳米片(图2L和S5O)。” 同样,在右栏中,更正的底部段落应为:“类肽N(FKF)显示R H居中于108 nm左右的组件(图4B),这可能表示较大的组件(图2D–F)。N(kFF)和N(KFF)主要显示出R H集中在0.5和44-49 nm附近的结构(图3C,D),分别对应于观察到的单体和小球。最后,在支持信息中,更正后的图S5和标题应如下所示(主要文字更改为黑体))。图S5。低温TEM观测概述。序列N(FkF),N(FKF),N(KFF)和N(kFF)按行排列。所有样品均由2 wt%(20 mg / mL)的溶液制备。左侧的两列与正文的​​图3相同,而右侧的两列显示了其他区域。成像的特征既包括典型的一些较少见的结构,包括(H)中的N(FKF)纤维束,也包括跨越(N和O)的N(kFF)的片状结构。150 nm×500 nm。个别直径小于50 nm的少量高对比度球状星团(A,右下; D,左下; M,左上)可能被冰污染了。” 本文引用了其他1个出版物。
更新日期:2020-10-21
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