Subunit of the protein translocation channel SecYEG. Component of the Sec protein translocase complex. Heterotrimer consisting of SecY, SecE and SecG subunits. The heterotrimers can form oligomers, although 1 heterotrimer is thought to be able to translocate proteins. Interacts with SecDF, and other proteins may be involved. The channel interacts with SecA via subunit SecY. Belongs to the SecG family.