Incorporation of non-canonical amino acids (ncAAs) can endow proteins with novel functionalities, such as crosslinking or fluorescence. In ion channels, the function of these variants can be studied with great precision using standard electrophysiology, but this approach is typically labor intensive and low throughput. Here, we establish a high-throughput protocol to conduct functional and pharmacological investigations of ncAA-containing hASIC1a (human acid-sensing ion channel 1a) variants in transiently transfected mammalian cells. We introduce three different photocrosslinking ncAAs into 103 positions and assess the function of the resulting 309 variants with automated patch-clamp (APC). We demonstrate that the approach is efficient and versatile, as it is amenable to assessing even complex pharmacological modulation by peptides. The data show that the acidic pocket is a major determinant for current decay and live-cell crosslinking provides insight into the hASIC1a-psalmotoxin-1 interaction. Further, we provide evidence that the protocol can be applied to other ion channels, such as P2X2 and GluA2 receptors. We therefore anticipate the approach to enable future APC-based studies of ncAA-containing ion channels in mammalian cells.

中文翻译：

---

高通量表征带有光交联剂的离子通道变体，以定位对功能和药理学至关重要的残基

掺入非规范氨基酸（ncAAs）可使蛋白质具有新功能，例如交联或荧光。在离子通道中，可以使用标准电生理学非常精确地研究这些变体的功能，但是这种方法通常劳动强度大且通量低。在这里，我们建立了一个高通量的协议，以进行瞬时转染的哺乳动物细胞中含有ncAA的hASIC1a（人类酸敏感离子通道1a）变体的功能和药理研究。我们将三种不同的光交联ncAA引入103个位置，并使用自动膜片钳（APC）评估了309个变体的功能。我们证明了该方法是有效且通用的，因为它可以评估甚至由肽组成的复杂药理学调节。数据表明酸性袋是电流衰减的主要决定因素，活细胞交联可深入了解hASIC1a-psalmotoxin-1的相互作用。此外，我们提供的证据表明该协议可以应用于其他离子通道，例如P2X2和GluA2受体。因此，我们期望该方法能够在哺乳动物细胞中实现基于APC的含ncAA离子通道的未来研究。