2i46
From Proteopedia
(New page: 200px<br /> <applet load="2i46" size="450" color="white" frame="true" align="right" spinBox="true" caption="2i46, resolution 2.7Å" /> '''Crystal structure of...) |
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caption="2i46, resolution 2.7Å" /> | caption="2i46, resolution 2.7Å" /> | ||
'''Crystal structure of human TPP1'''<br /> | '''Crystal structure of human TPP1'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Telomeres were originally defined as chromosome caps that prevent the | + | Telomeres were originally defined as chromosome caps that prevent the natural ends of linear chromosomes from undergoing deleterious degradation and fusion events. POT1 (protection of telomeres) protein binds the single-stranded G-rich DNA overhangs at human chromosome ends and suppresses unwanted DNA repair activities. TPP1 is a previously identified binding partner of POT1 that has been proposed to form part of a six-protein shelterin complex at telomeres. Here, the crystal structure of a domain of human TPP1 reveals an oligonucleotide/oligosaccharide-binding fold that is structurally similar to the beta-subunit of the telomere end-binding protein of a ciliated protozoan, suggesting that TPP1 is the missing beta-subunit of human POT1 protein. Telomeric DNA end-binding proteins have generally been found to inhibit rather than stimulate the action of the chromosome end-replicating enzyme, telomerase. In contrast, we find that TPP1 and POT1 form a complex with telomeric DNA that increases the activity and processivity of the human telomerase core enzyme. We propose that POT1-TPP1 switches from inhibiting telomerase access to the telomere, as a component of shelterin, to serving as a processivity factor for telomerase during telomere extension. |
==About this Structure== | ==About this Structure== | ||
| - | 2I46 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http:// | + | 2I46 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2I46 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Baciu, P.]] | [[Category: Baciu, P.]] | ||
| - | [[Category: Cech, T | + | [[Category: Cech, T R.]] |
[[Category: Else, T.]] | [[Category: Else, T.]] | ||
| - | [[Category: Hammer, G | + | [[Category: Hammer, G D.]] |
[[Category: Lei, M.]] | [[Category: Lei, M.]] | ||
| - | [[Category: Podell, E | + | [[Category: Podell, E R.]] |
[[Category: Wang, F.]] | [[Category: Wang, F.]] | ||
| - | [[Category: Yang, Y | + | [[Category: Yang, Y T.]] |
| - | [[Category: Zaug, A | + | [[Category: Zaug, A J.]] |
[[Category: ob fold]] | [[Category: ob fold]] | ||
[[Category: pot1 binding]] | [[Category: pot1 binding]] | ||
[[Category: tpp1]] | [[Category: tpp1]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:48:49 2008'' |
Revision as of 15:48, 21 February 2008
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Crystal structure of human TPP1
Overview
Telomeres were originally defined as chromosome caps that prevent the natural ends of linear chromosomes from undergoing deleterious degradation and fusion events. POT1 (protection of telomeres) protein binds the single-stranded G-rich DNA overhangs at human chromosome ends and suppresses unwanted DNA repair activities. TPP1 is a previously identified binding partner of POT1 that has been proposed to form part of a six-protein shelterin complex at telomeres. Here, the crystal structure of a domain of human TPP1 reveals an oligonucleotide/oligosaccharide-binding fold that is structurally similar to the beta-subunit of the telomere end-binding protein of a ciliated protozoan, suggesting that TPP1 is the missing beta-subunit of human POT1 protein. Telomeric DNA end-binding proteins have generally been found to inhibit rather than stimulate the action of the chromosome end-replicating enzyme, telomerase. In contrast, we find that TPP1 and POT1 form a complex with telomeric DNA that increases the activity and processivity of the human telomerase core enzyme. We propose that POT1-TPP1 switches from inhibiting telomerase access to the telomere, as a component of shelterin, to serving as a processivity factor for telomerase during telomere extension.
About this Structure
2I46 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
The POT1-TPP1 telomere complex is a telomerase processivity factor., Wang F, Podell ER, Zaug AJ, Yang Y, Baciu P, Cech TR, Lei M, Nature. 2007 Feb 1;445(7127):506-10. Epub 2007 Jan 21. PMID:17237768
Page seeded by OCA on Thu Feb 21 17:48:49 2008
Categories: Homo sapiens | Single protein | Baciu, P. | Cech, T R. | Else, T. | Hammer, G D. | Lei, M. | Podell, E R. | Wang, F. | Yang, Y T. | Zaug, A J. | Ob fold | Pot1 binding | Tpp1
