Figure 5.

Orthogonality matrix between encoded ncAAs and their exogenous cognate reaction partners used in the Table 1 DEAL papers. The matrix coloring indicates observed reactivity (green), non-reactivity (dark gray) or lack of information (white) for an encoded ncAA handle (identified by a letter) paired with a possible exogenous labeling groups (identified by a number). The background colors on which compounds are shown group them into subsets with similar reaction chemistry (e.g. azide-alkyne, and IEDDA cycloadditions, oxime ligation, and CRACR). The dashed planchette illustrates a useful way of using this matrix to select chemically orthogonal groups. A suitable chemically orthogonal pair of reactions will have two opposite corners of the rectangle in green boxes – indicating cognate handle-label pairs that react well (green dots here and green arrows in Figure 4A) – and will have the two opposite corners of the rectangle in gray boxes – indicating that the “noncognate off-target” reactions (red dots here and red arrows in Figure 4A) do not occur. The suitable pair illustrated with the rectangle shown was used by Bednar et al., 2021¹.