1i4a
From Proteopedia
(New page: 200px<br /><applet load="1i4a" size="450" color="white" frame="true" align="right" spinBox="true" caption="1i4a, resolution 2.0Å" /> '''CRYSTAL STRUCTURE OF ...) |
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| - | [[Image:1i4a.gif|left|200px]]<br /><applet load="1i4a" size=" | + | [[Image:1i4a.gif|left|200px]]<br /><applet load="1i4a" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1i4a, resolution 2.0Å" /> | caption="1i4a, resolution 2.0Å" /> | ||
'''CRYSTAL STRUCTURE OF PHOSPHORYLATION-MIMICKING MUTANT T6D OF ANNEXIN IV'''<br /> | '''CRYSTAL STRUCTURE OF PHOSPHORYLATION-MIMICKING MUTANT T6D OF ANNEXIN IV'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Site-directed mutagenesis, electron microscopy, and X-ray crystallography | + | Site-directed mutagenesis, electron microscopy, and X-ray crystallography were used to probe the structural basis of annexin IV-induced membrane aggregation and the inhibition of this property by protein kinase C phosphorylation. Site-directed mutants that either mimic (Thr6Asp, T6D) or prevent (Thr6Ala, T6A) phosphorylation of threonine 6 were produced for these studies and compared with wild-type annexin IV. In vitro assays showed that unmodified wild-type annexin IV and the T6A mutant, but not PKC-phosphorylated wild-type or the T6D mutant, promote vesicle aggregation. Electron crystallographic data of wild-type and T6D annexin IV revealed that, similar to annexin V, the annexin IV proteins form 2D trimer-based ordered arrays on phospholipid monolayers. Cryo-electron microscopic images of junctions formed between lipid vesicles in the presence of wild-type annexin IV indicated a separation distance corresponding to the thickness of two layers of membrane-bound annexin IV. In this orientation, a single layer of WT annexin IV, attached to the outer leaflet of one vesicle, would undergo face-to-face self-association with the annexin layer of a second vesicle. The 2.0-A resolution crystal structure of the T6D mutant showed that the mutation causes release of the N-terminal tail from the protein core. This change would preclude the face-to-face annexin self-association required to aggregate vesicles. The data suggest that reversible complex formation through phosphorylation and dephosphorylation could occur in vivo and play a role in the regulation of vesicle trafficking following changes in physiological states. |
==About this Structure== | ==About this Structure== | ||
| - | 1I4A is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with CA and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1I4A is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] 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=1I4A OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Brisson, A.]] | [[Category: Brisson, A.]] | ||
[[Category: Campos, B.]] | [[Category: Campos, B.]] | ||
| - | [[Category: Dedman, J | + | [[Category: Dedman, J R.]] |
| - | [[Category: Kaetzel, M | + | [[Category: Kaetzel, M A.]] |
| - | [[Category: Mealy, T | + | [[Category: Mealy, T R.]] |
| - | [[Category: Mo, Y | + | [[Category: Mo, Y D.]] |
| - | [[Category: Seaton, B | + | [[Category: Seaton, B A.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: SO4]] | [[Category: SO4]] | ||
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[[Category: phosphorylation mutant]] | [[Category: phosphorylation mutant]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:07:50 2008'' |
Revision as of 11:07, 21 February 2008
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CRYSTAL STRUCTURE OF PHOSPHORYLATION-MIMICKING MUTANT T6D OF ANNEXIN IV
Overview
Site-directed mutagenesis, electron microscopy, and X-ray crystallography were used to probe the structural basis of annexin IV-induced membrane aggregation and the inhibition of this property by protein kinase C phosphorylation. Site-directed mutants that either mimic (Thr6Asp, T6D) or prevent (Thr6Ala, T6A) phosphorylation of threonine 6 were produced for these studies and compared with wild-type annexin IV. In vitro assays showed that unmodified wild-type annexin IV and the T6A mutant, but not PKC-phosphorylated wild-type or the T6D mutant, promote vesicle aggregation. Electron crystallographic data of wild-type and T6D annexin IV revealed that, similar to annexin V, the annexin IV proteins form 2D trimer-based ordered arrays on phospholipid monolayers. Cryo-electron microscopic images of junctions formed between lipid vesicles in the presence of wild-type annexin IV indicated a separation distance corresponding to the thickness of two layers of membrane-bound annexin IV. In this orientation, a single layer of WT annexin IV, attached to the outer leaflet of one vesicle, would undergo face-to-face self-association with the annexin layer of a second vesicle. The 2.0-A resolution crystal structure of the T6D mutant showed that the mutation causes release of the N-terminal tail from the protein core. This change would preclude the face-to-face annexin self-association required to aggregate vesicles. The data suggest that reversible complex formation through phosphorylation and dephosphorylation could occur in vivo and play a role in the regulation of vesicle trafficking following changes in physiological states.
About this Structure
1I4A is a Single protein structure of sequence from Bos taurus with and as ligands. Full crystallographic information is available from OCA.
Reference
Phosphorylation mutants elucidate the mechanism of annexin IV-mediated membrane aggregation., Kaetzel MA, Mo YD, Mealy TR, Campos B, Bergsma-Schutter W, Brisson A, Dedman JR, Seaton BA, Biochemistry. 2001 Apr 3;40(13):4192-9. PMID:11300800
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