Figure 6. Comparison of binding of Mn²⁺-DTPA-(A)-H2, chemical shift differences and ¹⁵N{¹H}-NOEs of wild type and mutants of RXFP_(1–72).

The first column is the difference (mutant less wild type) in peak intensities from a titration of 50 μM mutant and wild-type LDLa-linker with 0.2 μM Mn²⁺-DTPA-(A)-H2. A positive difference indicates less binding of Mn²⁺-DTPA-(A)-H2 to the mutants. The second column is the average ¹HN and ¹⁵N chemical shift differences (Δδ) of mutant to wild-type protein. The third column is the difference (wild-type less mutant) of ¹⁵N{¹H}-NOE of mutant and wild-type LDLa-linker. A positive difference indicates a lower ¹⁵N{¹H}-NOE in the mutant. Experiments were conducted at pH 6.8 and 25 °C on (a) G41A/D42A, (b) N43A/N44A, (c) G45A/W46A, (d) F50A, and (e) F54A/Y58A. Additional mutants and data are in Supplementary Fig. 6.