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Paramyxovirinae P phosphoprotein C-terminal region The subfamily Paramyxovirinae of the family Paramyxoviridae now contains as main genera the Rubulaviruses, avulaviruses, respiroviruses, Henipavirus-es and morbilliviruses. Protein P is the best characterized, structurally of the replicative complex of N, P and L proteins and consists of two functionally distinct moieties, an N-terminal PNT, and a C-terminal PCT. The P protein is an essential part of the viral RNA polymerase complex formed from the P and L proteins. P protein plays a crucial role in the enzyme by positioning L onto the N/RNA template through an interaction with the C-terminal domain of N. Without P, L is not functional.The C-terminal part of P (PCT) is only functional as an oligomer and forms with L the polymerase complex. PNT is poorly conserved and unstructured in solution while PCT contains the oligomerization domain (PMD) that folds as a homotetrameric coiled coil (40) containing the L binding region and a C-terminal partially folded domain, PX (residues 474 to 568), identified as the nucleocapsid binding site. Interestingly, PX is also expressed as an independent polypeptide in infected cells. PX has a C-subdomain (residues 516 to 568) that consists of three {alpha}-helices arranged in an antiparallel triple-helical bundle linked to an unfolded flexible N-subdomain (residues 474 to 515). |
Jiyao W et al.(2023). "The conserved domain database in 2023.",