QVQLQESGGGSVQAGGSLRLSCAAPGGTFSSYAMGWFRQAPGKERDIVAAINWSGNVRYYGDSVKGRFTISRDNTKNTVYLQMSSLEPEDSAIYTCASGGTTATMRRGSIDYWGQGTQVTVSSAAAYPYDVPDYGSHHHHHH
28F6 is a nanobody designed to stabilize the iron-binding protein frataxin, acting as a chaperone in Friedreich's ataxia disease. The protein construct used for SAS contains an additional C-terminal polyhistidine tag.