1xyd
From Proteopedia
(New page: 200px<br /><applet load="1xyd" size="450" color="white" frame="true" align="right" spinBox="true" caption="1xyd" /> '''NMR Solution Structure of Rat Zinc-Calcium-S...) |
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'''NMR Solution Structure of Rat Zinc-Calcium-S100B, 20 Structures'''<br /> | '''NMR Solution Structure of Rat Zinc-Calcium-S100B, 20 Structures'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The EF-hand calcium-binding protein S100B also binds one zinc ion per | + | The EF-hand calcium-binding protein S100B also binds one zinc ion per subunit with a relatively high affinity (K(d) approximately 90 nM) [Wilder et al., (2003) Biochemistry 42, 13410-13421]. In this study, the structural characterization of zinc binding to calcium-loaded S100B was examined using high-resolution NMR techniques, including structural characterization of this complex in solution at atomic resolution. As with other S100 protein structures, the quaternary structure of Zn(2+)-Ca(2+)-bound S100B was found to be dimeric with helices H1, H1', H4, and H4' forming an X-type four-helix bundle at the dimer interface. NMR data together with mutational analyses are consistent with Zn(2+) coordination arising from His-15 and His-25 of one S100B subunit and from His-85 and Glu-89 of the other subunit. The addition of Zn(2+) was also found to extend helices H4 and H4' three to four residues similar to what was previously observed with the binding of target proteins to S100B. Furthermore, a kink in helix 4 was observed in Zn(2+)-Ca(2+)-bound S100B that is not in Ca(2+)-bound S100B. These structural changes upon Zn(2+)-binding could explain the 5-fold increase in affinity that Zn(2+)-Ca(2+)-bound S100B has for peptide targets such as the TRTK peptide versus Ca(2+)-bound S100B. There are also changes in the relative positioning of the two EF-hand calcium-binding domains and the respective helices comprising these EF-hands. Changes in conformation such as these could contribute to the order of magnitude higher affinity that S100B has for calcium in the presence of Zn(2+). |
==About this Structure== | ==About this Structure== | ||
| - | 1XYD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with CA and ZN as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1XYD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=ZN:'>ZN</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XYD OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Rattus norvegicus]] | [[Category: Rattus norvegicus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Varney, K | + | [[Category: Varney, K M.]] |
| - | [[Category: Weber, D | + | [[Category: Weber, D J.]] |
| - | [[Category: Wilder, P | + | [[Category: Wilder, P T.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: ZN]] | [[Category: ZN]] | ||
[[Category: metal binding protein]] | [[Category: metal binding protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:59:55 2008'' |
Revision as of 13:59, 21 February 2008
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NMR Solution Structure of Rat Zinc-Calcium-S100B, 20 Structures
Overview
The EF-hand calcium-binding protein S100B also binds one zinc ion per subunit with a relatively high affinity (K(d) approximately 90 nM) [Wilder et al., (2003) Biochemistry 42, 13410-13421]. In this study, the structural characterization of zinc binding to calcium-loaded S100B was examined using high-resolution NMR techniques, including structural characterization of this complex in solution at atomic resolution. As with other S100 protein structures, the quaternary structure of Zn(2+)-Ca(2+)-bound S100B was found to be dimeric with helices H1, H1', H4, and H4' forming an X-type four-helix bundle at the dimer interface. NMR data together with mutational analyses are consistent with Zn(2+) coordination arising from His-15 and His-25 of one S100B subunit and from His-85 and Glu-89 of the other subunit. The addition of Zn(2+) was also found to extend helices H4 and H4' three to four residues similar to what was previously observed with the binding of target proteins to S100B. Furthermore, a kink in helix 4 was observed in Zn(2+)-Ca(2+)-bound S100B that is not in Ca(2+)-bound S100B. These structural changes upon Zn(2+)-binding could explain the 5-fold increase in affinity that Zn(2+)-Ca(2+)-bound S100B has for peptide targets such as the TRTK peptide versus Ca(2+)-bound S100B. There are also changes in the relative positioning of the two EF-hand calcium-binding domains and the respective helices comprising these EF-hands. Changes in conformation such as these could contribute to the order of magnitude higher affinity that S100B has for calcium in the presence of Zn(2+).
About this Structure
1XYD is a Single protein structure of sequence from Rattus norvegicus with and as ligands. Full crystallographic information is available from OCA.
Reference
Solution structure of zinc- and calcium-bound rat S100B as determined by nuclear magnetic resonance spectroscopy., Wilder PT, Varney KM, Weiss MB, Gitti RK, Weber DJ, Biochemistry. 2005 Apr 19;44(15):5690-702. PMID:15823027
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