T7 RNA Polymerase: Difference between revisions

Line 9:

'''Catalysis'''. The enzyme then <scene name='77/778917/T7rp_gg_bound/1'>binds the first two substrate NTP's</scene>, as directed by the template (typically two GTP's, encoded by CC in the template strand). The <scene name='77/778917/T7rp_gg_phosphoryl_xfer/2'>3' hydroxyl of the +1 NTP attacks the alpha phosphate of the +2 NTP</scene> to initiate a phosphoryl transfer reaction. Release of pyrophosphate (PPi) leaves the product dinucleotide (pppGpG) in the active site. Note that one of the <scene name='77/778917/T7rp_mg_stabilizes_rxn/1'>Mg(II) ions is poised to stabilize</scene> the trigonal bipyramidal reaction intermediate (not shown) in this SN2 phosphoryl transfer reaction.

'''Movement'''. At this point, the complex is in the <scene name='77/778917/T7rp_init_pretranslocated/1'>pre-translocated state</scene> and to add the next base, the enzyme must translocate forward along the DNA (or equivalently, the RNA/DNA slides backwards), forming the post-translocated state. In the latter state (only) the active site now accommodates binding of the next NTP to the (+3) template base, to then <scene name='77/778917/T7rp_init_ggg/1'>form a 3 base transcript</scene>.

'''Movement'''. At this point, the complex is in the <scene name='77/778917/T7rp_init_pretranslocated/1'>pre-translocated state</scene> and to add the next base, the enzyme must translocate forward along the DNA (or equivalently, the RNA/DNA slides backwards), forming the post-translocated state. In the latter state (only) the active site now accommodates binding of the next NTP to the (+3) template base, to then <scene name='77/778917/T7rp_init_ggg/3'>form a 3 base transcript</scene>.

This cycle of NTP binding, catalysis (bond formation via phosporyl transfer), and forward translocation repeats over and over, throughout extension of the RNA.

T7 RNA Polymerase: Difference between revisions

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@@ Line 9: / Line 9: @@
 '''Catalysis'''. The enzyme then <scene name='77/778917/T7rp_gg_bound/1'>binds the first two substrate NTP's</scene>, as directed by the template (typically two GTP's, encoded by CC in the template strand). The <scene name='77/778917/T7rp_gg_phosphoryl_xfer/2'>3' hydroxyl of the +1 NTP attacks the alpha phosphate of the +2 NTP</scene> to initiate a phosphoryl transfer reaction. Release of pyrophosphate (PPi) leaves the product dinucleotide (pppGpG) in the active site. Note that one of the <scene name='77/778917/T7rp_mg_stabilizes_rxn/1'>Mg(II) ions is poised to stabilize</scene> the trigonal bipyramidal reaction intermediate (not shown) in this SN2 phosphoryl transfer reaction.
-'''Movement'''. At this point, the complex is in the <scene name='77/778917/T7rp_init_pretranslocated/1'>pre-translocated state</scene> and to add the next base, the enzyme must translocate forward along the DNA (or equivalently, the RNA/DNA slides backwards), forming the post-translocated state. In the latter state (only) the active site now accommodates binding of the next NTP to the (+3) template base, to then <scene name='77/778917/T7rp_init_ggg/1'>form a 3 base transcript</scene>.
+'''Movement'''. At this point, the complex is in the <scene name='77/778917/T7rp_init_pretranslocated/1'>pre-translocated state</scene> and to add the next base, the enzyme must translocate forward along the DNA (or equivalently, the RNA/DNA slides backwards), forming the post-translocated state. In the latter state (only) the active site now accommodates binding of the next NTP to the (+3) template base, to then <scene name='77/778917/T7rp_init_ggg/3'>form a 3 base transcript</scene>.
 This cycle of NTP binding, catalysis (bond formation via phosporyl transfer), and forward translocation repeats over and over, throughout extension of the RNA.