rTRD01 is a TDP-43 ligand that binds to TDP-43’s RRM1 and RRM2 domains ( K d =89 uM for TDP-43 102–269 ). rTRD01 partially disrupts TDP-43’s interaction with the hexanucleotide RNA repeat of the disease-linked c9orf72 gene. rTRD01 can be used for the research of neurodegenerative diseases.