L-glutaminyl-[histone H2A] + S-adenosyl-L-methionine <=> N(5)-methyl-L-glutaminyl-[histone H2A] + S-adenosyl-L-homocysteine + H(+)
l-glutaminyl-[histone h2a] + s-adenosyl-l-methionine <=> n(5)-methyl-l-glutaminyl-[histone h2a] + s-adenosyl-l-homocysteine + h(+)