InterPro: IPR008940 Protein prenyltransferase

Protein prenyltransferases catalyze the transfer of the carbon moiety of C15 farnesyl pyrophosphate [1] or geranylgeranyl pyrophosphate synthase [2] to a conserved cysteine residue in a CaaX motif of protein and peptide substrates. The addition of a farnesyl group is required to anchor proteins to the cell membrane. In the 3D structure of a mammalian Ras farnesyltransferases (Ftase), both subunits are largely composed of alpha-helices. The alpha-2 to alpha-15 helices in the alpha subunit fold into a novel helical hairpin structure, resulting in a crescent-shape domain that envelopes part of the subunit. The 12 helices of the beta-subunit form an alpha-alpha barrel. Six additional helices connect the inner core of helices and form the outside of the helical barrel. A deep cleft surrounded by hydrophobic amino acids in the centre of the barrel is proposed as the FPP-binding pocket. A single Zn²⁺ ion is located at the junction between the hydrophilic surface groove near the subunit interface.