(A) Amino acid residues in the 14 Å cavity of HDAC1 that are
mutated in this study (yellow and green, ball and stick structures)
are highlighted in the HDAC1 crystal structure (shown as purple mesh, 4BKX). The metal ion
required for catalysis is shown as a gray sphere. (B) Catalytic domains
of the class I, II, and IV human HDAC proteins were aligned (ClustalW),
and residues located in the 14 Å internal cavity are shown. Residues
differing from the most highly conserved at each position are highlighted
in red. The numbering at the top is for HDAC1. (Genbank accession
numbers: HDAC1, Q13547.1; HDAC2, Q92769.2; HDAC3, NP_003874.2; HDAC4, AAD29046.1; HDAC5, AAD29047.1; HDAC6, AAD29048.1; HDAC7, NP_056216.2; HDAC8, CAB90213.1; HDAC9, AAK66821.1; HDAC10, NP_114408.3; and HDAC11, NP_079103.2.)