A Drosophila pattern recognition receptor contains a peptidoglycan docking groove and unusual L,D-carboxypeptidase activity.
Chang CI, Pili-Floury S, Herve M, Parquet C, Chelliah Y, Lemaitre B, Mengin-Lecreulx D, Deisenhofer J, PLoS Biol, 2004 Sep - link

Crystal structures of MAP kinase p38 complexed to the docking sites on its nuclear substrate MEF2A and activator MKK3b.
Chang CI, Xu BE, Akella R, Cobb MH, Goldsmith EJ, Mol Cell, 2002 Jun - link