Department of Biochemistry, University of Utah School of Medicine, Salt Lake City 84132, USA. rnd@snowbird.med.utah.edu
We have solved the crystal structure of the yeast histone acetyltransferase Hat1-acetyl coenzyme A (AcCoA) complex at 2.3 A resolution. Hat1 has an elongated, curved structure, and the AcCoA molecule is bound in a cleft on the concave surface of the protein, marking the active site of the enzyme. A channel of variable width and depth that runs across the protein is probably the binding site for the histone substrate. A model for histone H4 binding by Hat1 is discussed in terms of possible sources of specific lysine recognition by the enzyme. The structure of Hat1 provides a model for the structures of the catalytic domains of a protein superfamily that includes other histone acetyltransferases such as Gcn5 and CBP.