1tql: Difference between revisions

[[Image:1tql.gif|left|200px]]<br /><applet load="1tql" size="350" color="white" frame="true" align="right" spinBox="true"  

The active RNA-dependent RNA polymerase of poliovirus, 3Dpol, is generated by cleavage of the 3CDpro precursor protein, a protease that has no polymerase activity despite containing the entire polymerase domain. By intentionally disrupting a known and persistent crystal packing interaction, we have crystallized the poliovirus polymerase in a new space group and solved the complete structure of the protein at 2.0 A resolution. It shows that the N-terminus of fully processed 3Dpol is buried in a surface pocket where it makes hydrogen bonds that act to position Asp238 in the active site. Asp238 is an essential residue that selects for the 2' OH group of substrate rNTPs, as shown by a 2.35 A structure of a 3Dpol-GTP complex. Mutational, biochemical, and structural data further demonstrate that 3Dpol activity is exquisitely sensitive to mutations at the N-terminus. This sensitivity is the result of allosteric effects where the structure around the buried N-terminus directly affects the positioning of Asp238 in the active site.

1TQL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Human_poliovirus_1 Human poliovirus 1] with <scene name='pdbligand=ACY:'>ACY</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/RNA-directed_RNA_polymerase RNA-directed RNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.48 2.7.7.48] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TQL OCA].  

[[Category: Peersen, O B.]]

[[Category: Thompson, A A.]]

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