Sandbox Reserved 1683: Difference between revisions
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Influenza A uses its trimer subunits to bind the template strand: the host capped RNA is bound by the PB2 cap-binding domain, followed by the cleavage of the PA/P3 endonuclease domain. <ref name="Velthuis" /> As mentioned before, the cap-binding domain then rotates allowing the insertion of the 3' end of the capped RNA, and then initiation begins once GTP is added to the 3' end of the capped primer which has become templated by the second residue in the viral RNA template. <ref name="Velthuis" /> | Influenza A uses its trimer subunits to bind the template strand: the host capped RNA is bound by the PB2 cap-binding domain, followed by the cleavage of the PA/P3 endonuclease domain. <ref name="Velthuis" /> As mentioned before, the cap-binding domain then rotates allowing the insertion of the 3' end of the capped RNA, and then initiation begins once GTP is added to the 3' end of the capped primer which has become templated by the second residue in the viral RNA template. <ref name="Velthuis" /> | ||
Nucleotides are guided into the polymerase through the entry channel, which is made of highly conserved basic amino acids and consists of all three Influenza A RDRP subunits.<ref name="Velthuis" /> The priming loop is especially important, as it is a <scene name='89/891373/Beta_hairpin/4'>beta-hairpin</scene> that protrudes from the PB1 thumb domain and has the role of supporting the sugar-base of the initiating nucleotide and it contains <scene name='89/891373/Priming_loop/4'>conserved residues</scene> such as PRO651 and the catalytic ASP445-446.<ref name="Velthuis" /> Additionally, the hairpin contributes to endonuclease activity, guides the duplex template/copy dsRNA out of the active site, and confers some selectivity of oligonucleotide primers via steric hindrance in the active site <ref>PMID:27274864</ref>. | Nucleotides are guided into the polymerase through the entry channel, which is made of highly conserved basic amino acids and consists of all three Influenza A RDRP subunits.<ref name="Velthuis" /> The priming loop is especially important, as it is a <scene name='89/891373/Beta_hairpin/4'>beta-hairpin</scene> that protrudes from the PB1 thumb domain and has the role of supporting the sugar-base of the initiating nucleotide and it contains <scene name='89/891373/Priming_loop/4'>conserved residues</scene> such as PRO651 and the catalytic ASP445-446, which hydrogen bond to the backbone of the incoming nucleotide to stabilize it during polymerization.<ref name="Velthuis" /> Additionally, the hairpin contributes to endonuclease activity, guides the duplex template/copy dsRNA out of the active site, and confers some selectivity of oligonucleotide primers via steric hindrance in the active site <ref>PMID:27274864</ref>. | ||
== Conservation within Influenza A RDRP == | == Conservation within Influenza A RDRP == | ||
