Catalyzes the S-adenosyl-L-methionine-dependent formation of N(1)-methyladenine at position 22 (m1A22) in tRNA. adenosine(22) in tRNA + S-adenosyl-L-methionine = H(+) + N(1)-methyladenosine(22) in tRNA + S-adenosyl-L-homocysteine Belongs to the TrmK family. Truncated N-terminus. Truncated N-terminus.