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Catalytic Site Atlas Version 2.2.12
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CSA entry for 1bob
Original Entry
Title:
Acetyltransferase
Compound:
Histone acetyltransferase
Mutant:
No
UniProt/Swiss-Prot:
Q12341-HAT1_YEAST
EC Class:
2.3.1.48
Other CSA Entries:
Overview of all sites for 1bob
Homologues of 1bob
Entries for UniProt/Swiss-Prot: Q12341
Entries for EC: 2.3.1.48
Other Databases:
PDB entry: 1bob
PDBsum entry: 1bob
UniProt/Swiss-Prot: Q12341
IntEnz entry: 2.3.1.48
Literature Report:
Introduction:
Hat1, isolated from Saccharomyces cerevisiae, is a type B histone acetyltransferase. It catalyses the sequential acetylation of Lys12 and then Lys5 of newly synthesised histone H4 using acetyl-CoA as the source of the acetyl group. Hat1 associates with the accessory protein Hat2 before binding and acetylating H4. The complex is thought to also bind histone H3. The complex is then imported into the nucleus where the histones are deposited onto DNA with the aid of Hif1. Hat1 is unable to acetylate DNA-associated histones.
Mechanism:
Glu255 deprotonates Lys12 of H4 and the neutral amine is the nucleophile for attack on the carbonyl of acetyl-CoA. The resulting tetrahedral intermediate collapses back and eliminates CoAS-, which is protonated by an as yet unknown acid. The process is then repeated with Lys5 of H4.
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Found by:
Literature reference 

ResidueChainNumberUniProt numberFunctional part FunctionTargetDescription
GLUA 255 255Sidechain
Acid/baseSubstrate
Glu255 removes a proton from Lys12/Lys5 of H4 to produce the neutral amine, which is a better nucleophile for attack on acetyl CoA.
Evidence from paper Evidence concerns Evidence type
PubMed ID 10430873 Current protein Residue is positioned appropriately (ligand position known)
PubMed ID 10430873 Related protein: UniProt Q03330 Structural similarity to homologue of known mechanism
PubMed ID 10430873 Current protein Conservation of residue
Notes:

References:
Which EBI biological databases are available and how do I access them? EBI Site Map