XA21 mostly be made up of Serine-threonine kinase (STK),Transmembrane (TM), Leucine-rich repeat (LRR), Postential signal sequence(PSS) from C-end to N-end in turn.

• XA21蛋白质从C-端到N-端,主要由丝/苏氨酸激酶区(STK)、跨膜区(TM)、富亮氨酸重复区(LRR)和N-末端信号肽区(PSS)等结构域构成,推断认为,跨膜区或者连同信号肽一起可能对XA21蛋白质的亚细胞定位起决定作用。