Human Complement Protein C8: Crystal Structure and Analysis of Binding Interactions
Human C8 is part of the membrane attack complex (MAC) that assembles on bacterial cell membranes to form a lethal pore-like structure. The MAC is comprised of complement proteins C5b, C6, C7, C8 and C9. The 150-kDa C8 protein consists of three non-identical subunits (C8alpha, C8beta, C8gamma), arranged as a disulfide linked C8alpha-gamma heterodimer non-covalently associated with C8beta. C6, C7, C8alpha, C8beta and C9 are members of the 'MAC family' of proteins and are homologous to one another. Each MAC family protein contains disulfide rich N- and C-terminal modules and a central 40-kDa segment referred to the membrane attack complex/perforin (MACPF) domain. The role of C8 within the MAC is to initiate formation of a transmembrane pore consisting of 12-18 molecules of C9.
Chemistry, Physical Sciences and Mathematics, C8, Complement, cytolysin, MACPF, membrane attack complex, pore forming protein
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