Correlation of Structure and Function in the Human Hotdog-fold Enzyme hTHEM4
journal contributionposted on 21.08.2012, 00:00 by Hong Zhao, Kap Lim, Anthony Choudry, John A. Latham, Manish C. Pathak, Dennis Dominguez, Lusong Luo, Osnat Herzberg, Debra Dunaway-Mariano
Human THEM4 (hTHEM4) is comprised of a catalytically active hotdog-fold acyl-CoA thioesterase domain and an N-terminal domain of unknown fold and function. hTHEM4 has been linked to Akt1 regulation and cell apoptosis. Herein, we report the X-ray structure of hHTEM4 bound with undecan-2-one-CoA. Structure guided mutagenesis was carried out to confirm the catalytic residues. The N-terminal domain is shown to be partially comprised of irregular and flexible secondary structure, reminiscent of a protein-binding domain. We demonstrate direct hTHEM4-Akt1 binding by immunoprecipitation and by inhibition of Akt1 kinase activity, thus providing independent evidence that hTHEM4 is an Akt1 negative regulator.