EGFR kinase domain duplication mutant. The purified construct consists of amino acids 643-976 appended to amino acids 651-993 using mature protein numbering (UniProt Q504U8 numbering: 651-993 followed by a duplicated 643-977 region). The protein construct used for SAXS contains an additional N-terminal non-native 22 amino acid extension and polyhistidine tag (HHHHHHSSGVDLGTENLYFQSM).