As part of an in-depth characterization of nanobodies directed against the Chlorobium tepidum protein CtRoco, a bacterial LRRK2 homologue, chemical crosslinking combined with mass spectrometry (CX-MS) was performed. Two allosteric nanobodies binding to two different epitopes in the LRR and the Roc domain of CtRoco, respectively were analysed using the CID-cleavable crosslinker disuccinimidyl sulfoxide (DSSO).