Connected cavity structure enables prenyl elongation across the dimer interface in mutated geranylfarnesyl diphosphate synthase from Methanosarcina mazei

Abstract

The mechanism for product chain-length determination of geranylfarnesyl diphosphate synthase from the methanogenic archaeon Methanosarcina mazei was investigated by constructing mutants based on structural information. Among the mutants, in which each of the bulky residues that constitute the bottom of the product-accommodating cavity was replaced with alanine, those having mutations on an α-helix existing at the subunit interface yielded longer products. In particular, replacement of isoleucine 112 on the α-helix greatly elongated the product chain-length, probably by connecting the reaction cavities of two subunits across the dimer interface.