Catalytic tRNA acetyltransferase subunit of the elongator complex which is required for multiple tRNA modifications, including mcm5U (5-methoxycarbonylmethyl uridine), mcm5s2U (5-methoxycarbonylmethyl-2-thiouridine), and ncm5U (5-carbamoylmethyl uridine) (PubMed:15769872, PubMed:17018299, PubMed:18755837, PubMed:21912530, PubMed:31309145). In the elongator complex, acts as a tRNA uridine(34) acetyltransferase, which mediates formation of carboxymethyluridine in the wobble base at position 34 in tRNAs (By similarity). The complex functions as a gamma-toxin target (TOT); disruption of the complex confers resistance to Kluyveromyces lactis toxin zymocin (pGKL1 killer toxin) (PubMed:11296232). May also be involved in sensitivity to Pichia inositovora toxin (PubMed:13680368). Independently, ELP3 may be involved in polarized exocytosis (PubMed:15780940). acetyl-CoA + H2O + S-adenosyl-L-methionine + uridine(34) in tRNA = 5'-deoxyadenosine + carboxymethyluridine(34) in tRNA + CoA + 2 H(+) + L-methionine Binds 1 [4Fe-4S] cluster (PubMed:16420352). The cluster is coordinated with 3 cysteines and an exchangeable S-adenosyl-L-methionine (PubMed:16420352). The cluster is required for structural integrity of the elongator complex, while it is not required for catalytic activity (PubMed:18986986). tRNA modification; 5-methoxycarbonylmethyl-2-thiouridine-tRNA biosynthesis. Component of the elongator complex which consists of ELP1/IKI3, ELP2, ELP3, ELP4, ELP5/IKI1 and ELP6 (PubMed:10445034, PubMed:11435442, PubMed:11689709, PubMed:18986986, PubMed:27974378, PubMed:27872205). The elongator complex is composed of two copies of the Elp123 subcomplex (composed of ELP1/IKI3, ELP2 and ELP3) and two copies of the Elp456 subcomplex (composed of ELP4, ELP5/IKI1 and ELP6) (PubMed:27974378, PubMed:27872205). The Elp123 subcomplex forms a two-lobed scaffold, which binds the Elp456 subcomplex asymmetrically (PubMed:27974378, PubMed:27872205, PubMed:25960406). In each lobe, ELP2 is tightly sandwiched between ELP1/IKI3 and ELP3 (PubMed:31309145). The Elp123 subcomplex binds tRNA through ELP1/IKI3 and ELP3 and can bind 2 tRNAs simultaneously (PubMed:31309145). tRNA-binding induces conformational rearrangements which precisely position the targeted anticodon base in the active site (PubMed:31309145). ELP3 interacts with KTI11/DPH3 (PubMed:18986986, PubMed:27694803). ELP3 interacts with KTI12 (PubMed:15772087). The Elp456 subcomplex binds tRNA and has ATPase activity (PubMed:22343726). Sensitive to caffeine and thermal stress (PubMed:18627462). Resistance to zymocin (PubMed:27694803, PubMed:18627462). Present with 4760 molecules/cell in log phase SD medium. Belongs to the ELP3 family. The elongator complex was originally thought to play a role in transcription elongation. Was reported to display histone acetyltransferase activity and to acetylate histone H3 preferentially at 'Lys-14', and H4 preferentially at 'Lys-8' (PubMed:10445034, PubMed:11904415, PubMed:15138274). However, it was later shown that the effect on histone acetylation and chromatin regulation is indirect and that the elongator complex is primarily involved in tRNA modification (PubMed:17018299, PubMed:18986986, PubMed:21912530).