This is the non-catalytic subunit of the N-terminal acetyltransferase B complex (NatB), NAA25. The NatB complex catalyses the acetylation of the amino-terminal methionine residue of all proteins beginning with Met-Asp or Met-Glu and of some proteins beginning with Met-Asn or Met-Met [1-3]. In Saccharomyces cerevisiae this subunit is called MDM20 and in Schizosaccharomyces pombe it is called Arm1 NatB acetylates the Tpm1 protein and regulates and tropomyosin-actin interactions. This subunit is required by the NatB complex for the N-terminal acetylation of Tpm1 [1].

1: Mdm20 protein functions with Nat3 protein to acetylate Tpm1 protein and regulate tropomyosin-actin interactions in budding yeast. Singer JM, Shaw JM; Proc Natl Acad Sci U S A. 2003;100:7644-7649. PMID:12808144

2: Identification of the human N(alpha)-acetyltransferase complex B (hNatB): a complex important for cell-cycle progression. Starheim KK, Arnesen T, Gromyko D, Ryningen A, Varhaug JE, Lillehaug JR; Biochem J. 2008;415:325-331. PMID:18570629

3: Molecular Basis of Substrate Specific Acetylation by N-Terminal Acetyltransferase\tNatB. Hong H, Cai Y, Zhang S, Ding H, Wang H, Han A; Structure. 2017;25:641-649. PMID:28380339