Targeted reengineering of protein geranylgeranyltransferase type I selectivity functionally implicates active-site residues in protein-substrate recognition.

摘要: Posttranslational modifications are vital for the function of many proteins. Prenylation is one such modification, wherein protein geranylgeranyltransferase type I (GGTase-I) or farnesyltransferase (FTase) modify proteins by attaching a 20- 15-carbon isoprenoid group, respectively, to cysteine residue near C-terminus target protein. These enzymes require C-terminal Ca1a2X sequence on their substrates, with a1, a2, and X residues serving as substrate-recognition elements FTase and/or GGTase-I. While crystallographic structures rat GGTase-I show tightly packed hydrophobic a2 binding pocket, consistent preference moderately sized in functional impact enzyme-substrate contacts within this active site remains be determined. Using site-directed mutagenesis peptide substrate structure-activity studies, we have identified specific active-site involved recognition developed novel variants expanded/altered selectivity. The ability drastically alter selectivity mirrors similar behavior observed but employs mutation distinct set structurally homologous residues. Our work demonstrates that tunable may general phenomenon among multispecific posttranslational modification raises possibility variable orthologues from different organisms. Furthermore, herein can serve tools studying effects prenylation pathway