Fig. 4.

N1251 is a critical determinant of C20 binding. a ELISA of GST fusion proteins demonstrates that C20 recognizes both isoforms of L1. NN nonneuronal. b–d Truncation (b) and substitution (c,d) analysis demonstrates the requirement for the carboxy-terminal 9 amino acids, and the critical importance of N1251 for C20 binding by ELISA. e,f ELISA titration analysis (e) and immunoblotting (f) verify the data in d, extend it to N1251D, and confirm that the C20 epitope requirements are maintained under denaturing conditions