1k6m
From Proteopedia
(New page: 200px<br /> <applet load="1k6m" size="450" color="white" frame="true" align="right" spinBox="true" caption="1k6m, resolution 2.4Å" /> '''Crystal Structure of...) |
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| - | [[Image:1k6m.gif|left|200px]]<br /> | + | [[Image:1k6m.gif|left|200px]]<br /><applet load="1k6m" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1k6m" size=" | + | |
caption="1k6m, resolution 2.4Å" /> | caption="1k6m, resolution 2.4Å" /> | ||
'''Crystal Structure of Human Liver 6-Phosphofructo-2-Kinase/Fructose-2,6-Bisphosphatase'''<br /> | '''Crystal Structure of Human Liver 6-Phosphofructo-2-Kinase/Fructose-2,6-Bisphosphatase'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The crystal structures of the human liver | + | The crystal structures of the human liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase in three different liganding states were determined and compared with those of the rat testis isozyme. A set of amino acid sequence heterogeneity from the two distinct genes encoding the two different tissue isozymes leads to both global and local conformational differences that may cause the differences in catalytic properties of the two isozymes. The sequence differences in a beta-hairpin loop in the kinase domain causes a translational shift of several hydrophobic interactions in the dimeric contact region, and its propagation to the domains interface results in a 5 degrees twist of the entire bisphosphatase domain relative to the kinase domain. The bisphosphatase domain twist allows the dimeric interactions between the bisphosphatase domains, which are negligible in the testis enzyme, and as a result, the conformational stability of the domain is increased. Sequence polymorphisms also confer small but significant structural dissimilarities in the substrate-binding loops, allowing the differentiated catalytic properties between the two different tissue-type isozymes. Whereas the polymorphic sequence at the bisphosphatase-active pocket suggests a more suitable substrate binding, a similar extent of sequence differences at the kinase-active pocket confers a different mechanism of substrates bindings to the kinase-active pocket. It includes the ATP-sensitive unwinding of the switch helix alpha5, which is a characteristic ATP-dependent conformational change in the testis form. The sequence-dependent structural difference disallows the liver kinase to follow the ATP-switch mechanism. Altogether these suggest that the liver isoform has structural features more appropriate for an elevated bisphosphatase activity, compared with that of the testis form. The structural predisposition for bisphosphatase activity in the liver isozyme is consistent with the liver-unique glucose metabolic pathway, gluconeogenesis. |
==About this Structure== | ==About this Structure== | ||
| - | 1K6M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with PO4 and ATG as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1K6M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=PO4:'>PO4</scene> and <scene name='pdbligand=ATG:'>ATG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K6M OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Hasemann, C | + | [[Category: Hasemann, C A.]] |
| - | [[Category: Lee, Y | + | [[Category: Lee, Y H.]] |
[[Category: Li, Y.]] | [[Category: Li, Y.]] | ||
[[Category: Uyeda, K.]] | [[Category: Uyeda, K.]] | ||
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[[Category: tissue differentiation]] | [[Category: tissue differentiation]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:30:42 2008'' |
Revision as of 11:30, 21 February 2008
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Crystal Structure of Human Liver 6-Phosphofructo-2-Kinase/Fructose-2,6-Bisphosphatase
Overview
The crystal structures of the human liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase in three different liganding states were determined and compared with those of the rat testis isozyme. A set of amino acid sequence heterogeneity from the two distinct genes encoding the two different tissue isozymes leads to both global and local conformational differences that may cause the differences in catalytic properties of the two isozymes. The sequence differences in a beta-hairpin loop in the kinase domain causes a translational shift of several hydrophobic interactions in the dimeric contact region, and its propagation to the domains interface results in a 5 degrees twist of the entire bisphosphatase domain relative to the kinase domain. The bisphosphatase domain twist allows the dimeric interactions between the bisphosphatase domains, which are negligible in the testis enzyme, and as a result, the conformational stability of the domain is increased. Sequence polymorphisms also confer small but significant structural dissimilarities in the substrate-binding loops, allowing the differentiated catalytic properties between the two different tissue-type isozymes. Whereas the polymorphic sequence at the bisphosphatase-active pocket suggests a more suitable substrate binding, a similar extent of sequence differences at the kinase-active pocket confers a different mechanism of substrates bindings to the kinase-active pocket. It includes the ATP-sensitive unwinding of the switch helix alpha5, which is a characteristic ATP-dependent conformational change in the testis form. The sequence-dependent structural difference disallows the liver kinase to follow the ATP-switch mechanism. Altogether these suggest that the liver isoform has structural features more appropriate for an elevated bisphosphatase activity, compared with that of the testis form. The structural predisposition for bisphosphatase activity in the liver isozyme is consistent with the liver-unique glucose metabolic pathway, gluconeogenesis.
About this Structure
1K6M is a Single protein structure of sequence from Homo sapiens with and as ligands. Full crystallographic information is available from OCA.
Reference
Tissue-specific structure/function differentiation of the liver isoform of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase., Lee YH, Li Y, Uyeda K, Hasemann CA, J Biol Chem. 2003 Jan 3;278(1):523-30. Epub 2002 Oct 11. PMID:12379646
Page seeded by OCA on Thu Feb 21 13:30:42 2008
Categories: Homo sapiens | Single protein | Hasemann, C A. | Lee, Y H. | Li, Y. | Uyeda, K. | ATG | PO4 | Domain | Domain stability | Isoform | Tissue differentiation
