N-Acetyltransferase 4 (NAT4)

Nat4 was previously shown to acetylate the N termini of histones H2A and H4. The analysis of chimeric proteins with various N-terminal segments of histone H4 fused to iso-1-cytochrome c revealed that efficient acetylation by NatD required at least 30 to 50 amino acid residues of the N terminus of histone H4. This requirement for an extended N terminus is in marked contrast with the major N-terminal acetyl transferases, i.e., NatA, NatB, and NatC, which require as few as two specific residues and usually no more than four or five. The nat4-Delta strain showed several minor phenotypes, including sensitivity to 3-aminotriazole, benomyl, and thiabendazole. Moreover, these nat4-Delta phenotypes were enhanced in the strain containing K5R K8R K12R replacements in the N-tail of histone H4, suggesting that the lack of N-terminal serine acetylation is synergistic to the lack of acetylation of the H4 N-tail lysines.