1anx: Difference between revisions
New page: left|200px<br /> <applet load="1anx" size="450" color="white" frame="true" align="right" spinBox="true" caption="1anx, resolution 1.90Å" /> '''THE CRYSTAL STRUCTU... |
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[[Image:1anx.gif|left|200px]]<br /> | [[Image:1anx.gif|left|200px]]<br /><applet load="1anx" size="350" color="white" frame="true" align="right" spinBox="true" | ||
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caption="1anx, resolution 1.90Å" /> | caption="1anx, resolution 1.90Å" /> | ||
'''THE CRYSTAL STRUCTURE OF A NEW HIGH-CALCIUM FORM OF ANNEXIN V'''<br /> | '''THE CRYSTAL STRUCTURE OF A NEW HIGH-CALCIUM FORM OF ANNEXIN V'''<br /> | ||
==Overview== | ==Overview== | ||
Annexin V was crystallized in the presence of a high concentration of | Annexin V was crystallized in the presence of a high concentration of calcium and the structure refined at 1.9 A resolution. The crystals are triclinic (P1) with three molecules per asymmetric unit and pseudo-R3 symmetry, reflecting a tendency of annexin to form trimers. The overall structure of the protein is similar to that seen in other crystal forms. There are, however, significant changes in domain III, where a new calcium site is formed. The whole region surrounding this site is reorganized in our structure, rendering annexin V more symmetrical and more alike annexin I. The formation of the new calcium site causes the displacement of Trp187 from a buried to an exposed conformation, a change that has recently been demonstrated by fluorescence measurements. The affinity of the different potential calcium sites is modulated: there is no calcium bound in domains II and IV, while up to two secondary calcium ions sites (in domains I and III) can substitute, depending on the calcium concentration present. We suggest that annexin can act as a calcium buffer, binding or releasing calcium depending on its local concentration. Our results also show that annexin displays inherent mobility which, together with its capacity to modulate the calcium affinity of its sites, can be of importance for its function on the membrane surface. | ||
==About this Structure== | ==About this Structure== | ||
1ANX 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 CA and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 1ANX 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=CA:'>CA</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ANX OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: calcium/phospholipid-binding protein]] | [[Category: calcium/phospholipid-binding protein]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:46:29 2008'' | ||
Revision as of 12:46, 21 February 2008
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THE CRYSTAL STRUCTURE OF A NEW HIGH-CALCIUM FORM OF ANNEXIN V
OverviewOverview
Annexin V was crystallized in the presence of a high concentration of calcium and the structure refined at 1.9 A resolution. The crystals are triclinic (P1) with three molecules per asymmetric unit and pseudo-R3 symmetry, reflecting a tendency of annexin to form trimers. The overall structure of the protein is similar to that seen in other crystal forms. There are, however, significant changes in domain III, where a new calcium site is formed. The whole region surrounding this site is reorganized in our structure, rendering annexin V more symmetrical and more alike annexin I. The formation of the new calcium site causes the displacement of Trp187 from a buried to an exposed conformation, a change that has recently been demonstrated by fluorescence measurements. The affinity of the different potential calcium sites is modulated: there is no calcium bound in domains II and IV, while up to two secondary calcium ions sites (in domains I and III) can substitute, depending on the calcium concentration present. We suggest that annexin can act as a calcium buffer, binding or releasing calcium depending on its local concentration. Our results also show that annexin displays inherent mobility which, together with its capacity to modulate the calcium affinity of its sites, can be of importance for its function on the membrane surface.
About this StructureAbout this Structure
1ANX is a Single protein structure of sequence from Homo sapiens with and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
The crystal structure of a new high-calcium form of annexin V., Sopkova J, Renouard M, Lewit-Bentley A, J Mol Biol. 1993 Dec 5;234(3):816-25. PMID:8254674
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