1exn
From Proteopedia
(New page: 200px<br /><applet load="1exn" size="450" color="white" frame="true" align="right" spinBox="true" caption="1exn, resolution 2.5Å" /> '''T5 5'-EXONUCLEASE'''<...) |
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| - | [[Image:1exn.jpg|left|200px]]<br /><applet load="1exn" size=" | + | [[Image:1exn.jpg|left|200px]]<br /><applet load="1exn" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1exn, resolution 2.5Å" /> | caption="1exn, resolution 2.5Å" /> | ||
'''T5 5'-EXONUCLEASE'''<br /> | '''T5 5'-EXONUCLEASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | THE 5'-exonucleases are enzymes that are essential for DNA replication and | + | THE 5'-exonucleases are enzymes that are essential for DNA replication and repair. As well as their exonucleolytic action, removing nucleotides from the 5'-end of nucleic acid molecules such as Okazaki fragments, many 5'-3'-exonucleases have been shown to possess endonucleolytic activities. T5 5'-3'-exonuclease shares many similarities with the amino terminal of eubacterial DNA polymerases, although, unlike eubacteria, phages such as T5, T4 and T7 express polymerase and 5'-exonuclease proteins from separate genes. Here we report the 2.5-A crystal structure of the phage T5 5'-exonuclease, which reveals a helical arch for binding DNA. We propose a model consistent with a threading mechanism in which single-stranded DNA could slide through the arch, which is formed by two helices, one containing positively charged, and the other hydrophobic, residues. The active site is at the base of the arch, and contains two metal-binding sites. |
==About this Structure== | ==About this Structure== | ||
| - | 1EXN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_phage_d3112 Pseudomonas phage d3112]. Active as [http://en.wikipedia.org/wiki/Exodeoxyribonuclease_(lambda-induced) Exodeoxyribonuclease (lambda-induced)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.11.3 3.1.11.3] Full crystallographic information is available from [http:// | + | 1EXN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_phage_d3112 Pseudomonas phage d3112]. Active as [http://en.wikipedia.org/wiki/Exodeoxyribonuclease_(lambda-induced) Exodeoxyribonuclease (lambda-induced)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.11.3 3.1.11.3] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EXN OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Pseudomonas phage d3112]] | [[Category: Pseudomonas phage d3112]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Ceska, T | + | [[Category: Ceska, T A.]] |
| - | [[Category: Sayers, J | + | [[Category: Sayers, J R.]] |
[[Category: Stier, G.]] | [[Category: Stier, G.]] | ||
[[Category: Suck, D.]] | [[Category: Suck, D.]] | ||
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[[Category: nuclease]] | [[Category: nuclease]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:32:39 2008'' |
Revision as of 10:32, 21 February 2008
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T5 5'-EXONUCLEASE
Overview
THE 5'-exonucleases are enzymes that are essential for DNA replication and repair. As well as their exonucleolytic action, removing nucleotides from the 5'-end of nucleic acid molecules such as Okazaki fragments, many 5'-3'-exonucleases have been shown to possess endonucleolytic activities. T5 5'-3'-exonuclease shares many similarities with the amino terminal of eubacterial DNA polymerases, although, unlike eubacteria, phages such as T5, T4 and T7 express polymerase and 5'-exonuclease proteins from separate genes. Here we report the 2.5-A crystal structure of the phage T5 5'-exonuclease, which reveals a helical arch for binding DNA. We propose a model consistent with a threading mechanism in which single-stranded DNA could slide through the arch, which is formed by two helices, one containing positively charged, and the other hydrophobic, residues. The active site is at the base of the arch, and contains two metal-binding sites.
About this Structure
1EXN is a Single protein structure of sequence from Pseudomonas phage d3112. Active as Exodeoxyribonuclease (lambda-induced), with EC number 3.1.11.3 Full crystallographic information is available from OCA.
Reference
A helical arch allowing single-stranded DNA to thread through T5 5'-exonuclease., Ceska TA, Sayers JR, Stier G, Suck D, Nature. 1996 Jul 4;382(6586):90-3. PMID:8657312
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