In humans, YTH (YT521-B homology) domain containing protein 2 (YTHDC2) plays a crucial role in the phase-shift from mitosis to meiosis. YTH domains bind to methylated adenosine nucleotides such as m6A. In a phylogenic tree, the YTH domain of YTHDC2 (YTH2) and that of the YTH containing protein YTHDC1 (YTH1) belong to the same sub-group. However, the binding affinity of m6A differs between these proteins. Here, we report 1H, 13C and 15N resonance assignment of YTH2 and its solution structure to examine the difference of the structural architecture and the dynamic properties of YTH1 and YTH2. YTH2 adopts a β1-α1-β2-α2-β3-β4-β5-α3-β6-α4 topology, which was also observed in YTH1. However, the β4-β5 loops of YTH1 and YTH2 are distinct in length and amino acid composition. Our data revealed that, unlike in YTH1, the structure of m6A-binding pocket of YTH2 formed by the β4-β5 loop is stabilized by electrostatic interaction. This assignment and the structural information for YTH2 will provide the insight on the further functional research of YTHDC2.
Keywords: Meiosis; N6-methylated adenosine; RNA binding domain; Spermatogonium; YTH domain; YTHDC2.