Differential Post-Translational Amino Acid Isomerization Found among Neuropeptides in Aplysia californica
Differential Post-Translational Amino Acid Isomerization Found among Neuropeptides in Aplysia californica
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DOI：
10.1021/acschembio.9b00910
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发表时间：
2020-01-01
影响因子：
4
通讯作者：
Sweedler, Jonathan V.
中科院分区：
文献类型：
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作者：
Mast, David H.;Checco, James W.;Sweedler, Jonathan V.
含D-氨基酸的肽（DAACP）是动物体内一类重要的后修饰肽，在细胞间信号转导中发挥重要作用。尽管L-至D-残基异构化的功能重要性，但对其普遍性知之甚少，主要是由于与检测肽立体化学差异相关的困难。先前发现DAACP的努力主要集中在基于与已知DAACP或DAACP编码前体的同源性来寻找肽。在这里，我们使用了酶筛选，质谱和色谱分析相结合，以确定新的DAACP在中枢神经系统（CNS）的Aussia californica。我们确定了五个新的DAACP从pleurin前体和三个DAACP从以前未知的蛋白质。此外，来自pleurin前体的两种肽Plrn 2和Plrn 3作为DAACP存在，在位置2或3处发现D-残基。Plrn 2和Plrn 3的这些差异修饰形式位于动物CNS的特定区域。Plrn 2和Plrn 3似乎是第一个在多于一个位置发现D-残基的动物DAACP，这表明L-至D-残基异构化可能是比以前认为的更可变/动态的修饰。总之，这项研究证明了非靶向DAACP发现方法用于鉴定新DAACP的实用性，并证明异构化在A.加利福尼亚州。
D-Amino acid-containing peptides (DAACPs) make up a class of post-translationally modified peptides in animals that play important roles as cell-to-cell signaling molecules. Despite the functional importance of L- to D-residue isomerization, little is known about its prevalence, mostly due to difficulties associated with detecting differences in peptide stereochemistry. Prior efforts to discover DAACPs have been largely focused on pursuing peptides based on homology to known DAACPs or DAACP-encoding precursors. Here, we used a combination of enzymatic screening, mass spectrometry, and chromatographic analysis to identify novel DAACPs in the central nervous system (CNS) of Aplysia californica. We identified five new DAACPs from the pleurin precursor and three DAACPs from previously uncharacterized proteins. In addition, two peptides from the pleurin precursor, Plrn2 and Plrn3, exist as DAACPs with the D-residue found at position 2 or 3. These differentially modified forms of Plrn2 and Plrn3 are located in specific regions of the animal's CNS. Plrn2 and Plrn3 appear to be the first animal DAACPs in which the D-residue is found at more than one position, and this suggests that L- to D-residue isomerization may be a more variable/dynamic modification than previously thought. Overall, this study demonstrates the utility of nontargeted DAACP discovery approaches for identifying new DAACPs and demonstrates that isomerization is prevalent throughout the CNS of A. californica.