Injectosomes in Gram-Positive Bacteria

摘要: Gram-positive bacteria are enclosed by a single membrane and therefore have apparently not evolved or acquired secretion systems similar to the type I, III, IV found in gram-negative bacteria. Although III gram-positive bacterial pathogens, these pathogens still translocate effectors into eukaryotic cells. This chapter examines structure-function aspects of cholesterol-dependent cytolysins (CDCs) how CDC mechanism has been adapted for use Streptococcus pyogenes form its injectosome. The most recognizable feature primary structure is conserved undecapeptide that located near carboxy terminus CDCs. CDCs highly soluble proteins once released from system cell; they undergo remarkable transition results their conversion molecules supramolecular pore-forming complex. S. injectosome composed two known components, SLO Sec-dependent pathway; combination, necessary translocation NAD+ glycohydrolase (SPN) cytoplasm human keratinocytes. SPN 52-kDa protein contains typical signal peptide supernatant cultured organisms. No SPN-related enzymes identified other bacteria, structurally related any protein. paradigm will impact several areas biology because many interesting questions posed this system.