The gspCDEFGHIJKLMO operon in E. coli contains a total of twelve genes, which encode for the proteins that make up the type II secretion system (T2SS) protein. The T2SS is responsible for moving proteins such as toxins and enzymes that cause symptoms associated with bacterial infection across the two cell membranes of the bacteria. This operon is regulated by DNA-binding protein H-NS, which binds to the DNA of the promoter, changing its conformation and preventing the RNA polymerase from binding to the promoter and transcribing the genes in the operon. The first gene, gspC, encodes for the putative T2SS protein C, which makes up part of the inner membrane complex of the secretion system, along with the proteins produced by gspF, gspL and gspM. After these, gspD encodes for the putative T2SS protein for export D, which forms a homo-pentadecamer pore in the outer membrane of the bacteria, which allows the exported substances to exit the cell. gspE encodes protein subunit E, which is the secretion ATPase. This protein binds to ATP and hydrolyzes it, and the energy produced by this is used to construct and deconstruct the pseudopillus, which is involved in the movement of substances across the periplasm and out of the cell. Another complex that is formed is the pseudopilus, which is made from pseudopilin proteins encoded by gspG, gspH, gspI, gspJ and gspK. These proteins are all activated by the leader peptidase integral membrane protein encoded by gspO, which is found in the inner membrane and allows for the formation of mature pseudopilin proteins.

Operon: General Secretory Pathway References