Binding of inhibitors to active-site mutants of CD1, the enigmatic catalytic domain of histone deacetylase 6

Acta Crystallogr F Struct Biol Commun. 2020 Sep 1;76(Pt 9):428-437. doi: 10.1107/S2053230X20010250. Epub 2020 Aug 19.

Abstract

The zinc hydrolase histone deacetylase 6 (HDAC6) is unique among vertebrate deacetylases in that it contains two catalytic domains, designated CD1 and CD2. Both domains are fully functional as lysine deacetylases in vitro. However, the in vivo function of only the CD2 domain is well defined, whereas that of the CD1 domain is more enigmatic. Three X-ray crystal structures of HDAC6 CD1-inhibitor complexes are now reported to broaden the understanding of affinity determinants in the active site. Notably, cocrystallization with inhibitors was facilitated by using active-site mutants of zebrafish HDAC6 CD1. The first mutant studied, H82F/F202Y HDAC6 CD1, was designed to mimic the active site of human HDAC6 CD1. The structure of its complex with trichostatin A was generally identical to that with the wild-type zebrafish enzyme. The second mutant studied, K330L HDAC6 CD1, was prepared to mimic the active site of HDAC6 CD2. It has previously been demonstrated that this substitution does not perturb inhibitor binding conformations in HDAC6 CD1; here, this mutant facilitated cocrystallization with derivatives of the cancer chemotherapy drug suberoylanilide hydroxamic acid (SAHA). These crystal structures allow the mapping of inhibitor-binding regions in the outer active-site cleft, where one HDAC isozyme typically differs from another. It is expected that these structures will help to guide the structure-based design of inhibitors with selectivity against HDAC6 CD1, which in turn will enable new chemical biology approaches to probe its cellular function.

Keywords: drug design; enzyme inhibitors; hydrolases; zinc enzymes.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antineoplastic Agents / chemistry*
  • Antineoplastic Agents / metabolism
  • Catalytic Domain
  • Cloning, Molecular
  • Crystallography, X-Ray
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Genetic Vectors / chemistry
  • Genetic Vectors / metabolism
  • Histone Deacetylase 6 / antagonists & inhibitors
  • Histone Deacetylase 6 / chemistry*
  • Histone Deacetylase 6 / genetics
  • Histone Deacetylase 6 / metabolism
  • Histone Deacetylase Inhibitors / chemistry*
  • Histone Deacetylase Inhibitors / metabolism
  • Humans
  • Hydroxamic Acids / chemistry*
  • Hydroxamic Acids / metabolism
  • Models, Molecular
  • Mutation
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Interaction Domains and Motifs
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Vorinostat / analogs & derivatives*
  • Vorinostat / metabolism
  • Zebrafish
  • Zebrafish Proteins / antagonists & inhibitors
  • Zebrafish Proteins / chemistry*
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism

Substances

  • Antineoplastic Agents
  • Histone Deacetylase Inhibitors
  • Hydroxamic Acids
  • Recombinant Proteins
  • Zebrafish Proteins
  • trichostatin A
  • Vorinostat
  • HDAC6 protein, human
  • HDAC6 protein, zebrafish
  • Histone Deacetylase 6