Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104, Freiburg, Germany.
Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef-Schneider-Str. 2, 97080, Würzburg, Germany.
Plant Cell Rep. 2024 Oct 3;43(10):250. doi: 10.1007/s00299-024-03329-1.
Analysis of the N-terminome of Physcomitrella reveals N-terminal monomethylation of nuclear-encoded, mitochondria-localized proteins. Post- or co-translational N-terminal modifications of proteins influence their half-life as well as mediating protein sorting to organelles via cleavable N-terminal sequences that are recognized by the respective translocation machinery. Here, we provide an overview on the current modification state of the N-termini of over 4500 proteins from the model moss Physcomitrella (Physcomitrium patens) using a compilation of 24 N-terminomics datasets. Our data reveal distinct proteoforms and modification states and confirm predicted targeting peptide cleavage sites of 1,144 proteins localized to plastids and the thylakoid lumen, to mitochondria, and to the secretory pathway. In addition, we uncover extended N-terminal methylation of mitochondrial proteins. Moreover, we identified PpNTM1 (P. patens alpha N-terminal protein methyltransferase 1) as a candidate for protein methylation in plastids, mitochondria, and the cytosol. These data can now be used to optimize computational targeting predictors, for customized protein fusions and their targeted localization in biotechnology, and offer novel insights into potential dual targeting of proteins.
对Physcomitrella 的 N 端组分析揭示了核编码、线粒体定位蛋白的 N 端单甲基化。蛋白质的翻译后或共翻译 N 端修饰会影响其半衰期，并通过可切割的 N 端序列介导蛋白质分拣到细胞器，这些序列被相应的易位机制识别。在这里，我们使用 24 个 N 端组学数据集的组合，对来自模式藓（Physcomitrium patens）的超过 4500 种蛋白质的 N 末端的当前修饰状态提供了一个概述。我们的数据揭示了不同的蛋白质形式和修饰状态，并证实了预测的 1144 种定位于质体和类囊体腔、线粒体和分泌途径的蛋白质的靶向肽切割位点。此外，我们还发现了线粒体蛋白的延伸 N 端甲基化。此外，我们还鉴定了 PpNTM1（Physcomitrella patens alpha N-terminal protein methyltransferase 1）作为质体、线粒体和细胞质中蛋白质甲基化的候选物。这些数据现在可用于优化计算靶向预测器，用于生物技术中的定制蛋白质融合及其靶向定位，并为蛋白质的潜在双重靶向提供新的见解。
