This is the N-terminal helical domain of protein arginine N-methyltransferase 3 (ANM3/PRMT3) which has a C2H2 zinc finger. ANM3 catalyses both the monomethylation and asymmetric dimethylation of the guanidino nitrogens of arginine residues in target proteins and may regulate retinoic acid synthesis and signaling by inhibiting ALDH1A1 retinal dehydrogenase activity [1]. PRMT3 orthologue from fission yeast, is a ribosomal protein that methylates guanidino nitrogens of arginyl residues in ribosomal protein rps2 and may regulate ribosome biosynthesis [2]. This ZnF is required for its optimal enzymatic activity and contributes to substrate specificity [1].

1: PRMT3 interacts with ALDH1A1 and regulates gene-expression by inhibiting retinoic acid signaling. Verma M, Khan MIK, Kadumuri RV, Chakrapani B, Awasthi S, Mahesh A, Govindaraju G, Chavali PL, Rajavelu A, Chavali S, Dhayalan A; Commun Biol. 2021;4:109. PMID:33495566

2: PRMT3 is a ribosomal protein methyltransferase that affects the cellular levels of ribosomal subunits. Bachand F, Silver PA; EMBO J. 2004;23:2641-2650. PMID:15175657