2atq
From Proteopedia
(New page: 200px<br /><applet load="2atq" size="450" color="white" frame="true" align="right" spinBox="true" caption="2atq, resolution 3.20Å" /> '''RB69 single-stranded...) |
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| - | [[Image:2atq.gif|left|200px]]<br /><applet load="2atq" size=" | + | [[Image:2atq.gif|left|200px]]<br /><applet load="2atq" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2atq, resolution 3.20Å" /> | caption="2atq, resolution 3.20Å" /> | ||
'''RB69 single-stranded DNA binding protein-DNA polymerase fusion'''<br /> | '''RB69 single-stranded DNA binding protein-DNA polymerase fusion'''<br /> | ||
==Overview== | ==Overview== | ||
| - | In vivo, replicative DNA polymerases are made more processive by their | + | In vivo, replicative DNA polymerases are made more processive by their interactions with accessory proteins at the replication fork. Single-stranded DNA binding protein (SSB) is an essential protein that binds tightly and cooperatively to single-stranded DNA during replication to remove adventitious secondary structures and protect the exposed DNA from endogenous nucleases. Using information from high resolution structures and biochemical data, we have engineered a functional chimeric enzyme of the bacteriophage RB69 DNA polymerase and SSB with substantially increased processivity. Fusion of RB69 DNA polymerase with its cognate SSB via a short six amino acid linker increases affinity for primer-template DNA by sixfold and subsequently increases processivity by sevenfold while maintaining fidelity. The crystal structure of this fusion protein was solved by a combination of multiwavelength anomalous diffraction and molecular replacement to 3.2 A resolution and shows that RB69 SSB is positioned proximal to the N-terminal domain of RB69 DNA polymerase near the template strand channel. The structural and biochemical data suggest that SSB interactions with DNA polymerase are transient and flexible, consistent with models of a dynamic replisome during elongation. |
==About this Structure== | ==About this Structure== | ||
| - | 2ATQ is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Enterobacteria_phage_rb18 Enterobacteria phage rb18] with ZN and GDP as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA-directed_DNA_polymerase DNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.7 2.7.7.7] Full crystallographic information is available from [http:// | + | 2ATQ is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Enterobacteria_phage_rb18 Enterobacteria phage rb18] with <scene name='pdbligand=ZN:'>ZN</scene> and <scene name='pdbligand=GDP:'>GDP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA-directed_DNA_polymerase DNA-directed DNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.7 2.7.7.7] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ATQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: thumb domain]] | [[Category: thumb domain]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:30:54 2008'' |
Revision as of 14:30, 21 February 2008
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RB69 single-stranded DNA binding protein-DNA polymerase fusion
Overview
In vivo, replicative DNA polymerases are made more processive by their interactions with accessory proteins at the replication fork. Single-stranded DNA binding protein (SSB) is an essential protein that binds tightly and cooperatively to single-stranded DNA during replication to remove adventitious secondary structures and protect the exposed DNA from endogenous nucleases. Using information from high resolution structures and biochemical data, we have engineered a functional chimeric enzyme of the bacteriophage RB69 DNA polymerase and SSB with substantially increased processivity. Fusion of RB69 DNA polymerase with its cognate SSB via a short six amino acid linker increases affinity for primer-template DNA by sixfold and subsequently increases processivity by sevenfold while maintaining fidelity. The crystal structure of this fusion protein was solved by a combination of multiwavelength anomalous diffraction and molecular replacement to 3.2 A resolution and shows that RB69 SSB is positioned proximal to the N-terminal domain of RB69 DNA polymerase near the template strand channel. The structural and biochemical data suggest that SSB interactions with DNA polymerase are transient and flexible, consistent with models of a dynamic replisome during elongation.
About this Structure
2ATQ is a Protein complex structure of sequences from Enterobacteria phage rb18 with and as ligands. Active as DNA-directed DNA polymerase, with EC number 2.7.7.7 Full crystallographic information is available from OCA.
Reference
Structure and enzymatic properties of a chimeric bacteriophage RB69 DNA polymerase and single-stranded DNA binding protein with increased processivity., Sun S, Geng L, Shamoo Y, Proteins. 2006 Oct 1;65(1):231-8. PMID:16881051
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