The tethered MBP-RAMP1 ECD-CLR ECD and MBP-RAMP2 ECD [L106R]-CLR ECD proteins were complexed with CGRP(27-37)NH2 [D31, P34, F35] or AM(25-52)NH2 and crystallized with a reservoir solution of 22% PEG3350, 8% Tacsimate (pH 6.0) for the CGRP receptor complex or 19% PEG3350, 0.1 M Tris-HCl (pH 8.3), 225 mM sodium acetate, and 20% ethylene glycol for the AM1 receptor complex. Diffraction data collected at the APS synchrotron were processed with HKL2000 (Otwinowski and Minor, 1997) and the CCP4 suite (Winn et al., 2011). The structures were solved by molecular replacement with Phaser (McCoy et al., 2007), rebuilt with COOT (Emsley et al., 2010), and refined with REFMAC5 (Murshudov et al., 1997). Details and homology modeling are in Supplemental Experimental Procedures.