Obscurin Ig57/58
These data were collected at Argonne National labs on obscurin Ig57/58, and were published in a 2019 Protein Science article (Whitley et al.). These data are on 2 Ig domains attached together with a flexible linker (pdb: 6MG9 for the first domain, 2MWC for the second domain; sequence 4248-4430 of accession number CAC44768.1). Thus, this protein fragment is flexible, and thus cannot be treated as a rigid body.
As a first approximation of the size, analyze the Guinier plot. A gnom/ATSAS analysis is will only be of limited use, due to flexibility. To really get at the flexibility issue, we recommend taking the data and either using SASSIE or MultiFOXS, both of which are free online servers.
Our tutorials of how to handle and analyze these data are in the 'SAXS Tutorial' files tab.