2. Academic Validation
  3. Structural basis for the target specificity of actin histidine methyltransferase SETD3

Structural basis for the target specificity of actin histidine methyltransferase SETD3

  • Nat Commun. 2019 Aug 6;10(1):3541. doi: 10.1038/s41467-019-11554-6.
Shaobo Dai 1,  John R Horton 1,  Clayton B Woodcock 1,  Alex W Wilkinson 2,  Xing Zhang 1,  Or Gozani 2,  Xiaodong Cheng 3
Affiliations

Affiliations

  • 1 Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.
  • 2 Department of Biology, Stanford University, Stanford, CA, 94305, USA.
  • 3 Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA. [email protected].
PMID: 31388018 DOI: 10.1038/s41467-019-11554-6
Abstract

SETD3 is an actin histidine-N3 methyltransferase, whereas other characterized SET-domain enzymes are protein lysine methyltransferases. We report that in a pre-reactive complex SETD3 binds the N3-protonated form (N3-H) of actin His73, and in a post-reactive product complex, SETD3 generates the methylated histidine in an N1-protonated (N1-H) and N3-methylated form. During the reaction, the imidazole ring of His73 rotates ~105°, which shifts the proton from N3 to N1, thus ensuring that the target atom N3 is deprotonated prior to the methyl transfer. Under the conditions optimized for lysine deprotonation, SETD3 has weak lysine methylation activity on an actin peptide in which the target His73 is substituted by a lysine. The structure of SETD3 with Lys73-containing peptide reveals a bent conformation of Lys73, with its side chain aliphatic carbons tracing along the edge of imidazole ring and the terminal ε-amino group occupying a position nearly identical to the N3 atom of unmethylated histidine.

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