National Center for
5G0I: Crystal Structure Of Danio Rerio Hdac6 Cd1 And Cd2 (linker Cleaved) In Complex With Nexturastat A
Nat. Chem. Biol. (2016) 12 p.748-754
We report crystal structures of zebrafish histone deacetylase 6 (HDAC6) catalytic domains in tandem or as single domains in complex with the (R) and (S) enantiomers of trichostatin A (TSA) or with the HDAC6-specific inhibitor nexturastat A. The tandem domains formed, together with the inter-domain linker, an ellipsoid-shaped complex with pseudo-twofold symmetry. We identified important active site differences between both catalytic domains and revealed the binding mode of HDAC6 selective inhibitors. HDAC inhibition assays with (R)- and (S)-TSA showed that (R)-TSA was a broad-range inhibitor, whereas (S)-TSA had moderate selectivity for HDAC6. We identified a uniquely positioned alpha-helix and a flexible tryptophan residue in the loop joining alpha-helices H20 to H21 as critical for deacetylation of the physiologic substrate tubulin. Using single-molecule measurements and biochemical assays we demonstrated that HDAC6 catalytic domain 2 deacetylated alpha-tubulin lysine 40 in the lumen of microtubules, but that its preferred substrate was unpolymerized tubulin.