In isolation, CASKIN2 SAM1 and SAM2 demonstrate different thermostabilities.
1H-15N HSQC spectra acquired at 700 MHz at a protein concentration of 100 μM in PBS buffer supplemented with 10 % D2O. At 25 °C, SAM1 appears to be partially unfolded as the spectrum shows poor amide resonance dispersion as well as fewer resonances than expected. When the SAM1 sample is reacquired at 5 °C, more resonances are apparent. In contrast, the spectrum of SAM2 suggests that it is folded at 25 °C. The spectrum of the SAM1-SAM2 tandem is not an addition of the individual SAM1 and SAM2 spectra suggesting an interaction between the two domains