In vivo analysis reveals substrate-gating mutants of a rhomboid intramembrane protease display increased activity in living cells.

ABSTRACT: Intramembrane proteases hydrolyze peptide bonds within cell membranes. Recent crystal structures revealed that rhomboid intramembrane proteases contain a hydrated active site that opens to the outside of the cell, but is protected laterally from membrane lipids by protein segments. Using Escherichia coli rhomboid (GlpG) structures as a guide, we previously took a mutational approach to identify the GlpG gating mechanism that allows substrates to enter the active site laterally from the membrane. Mutations that weaken contacts keeping the gate closed increase enzyme activity and implicate transmembrane segment 5 as the substrate gate. Since these analyses were performed in vitro with pure proteins in detergent micelles, we have now examined GlpG in its natural environment, within the membra

SUBMITTER: Urban S 

PROVIDER: S-EPMC2678756 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature