1euo
From Proteopedia
(New page: 200px<br /><applet load="1euo" size="450" color="white" frame="true" align="right" spinBox="true" caption="1euo, resolution 2.0Å" /> '''Crystal structure of ...) |
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| - | [[Image:1euo.jpg|left|200px]]<br /><applet load="1euo" size=" | + | [[Image:1euo.jpg|left|200px]]<br /><applet load="1euo" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1euo, resolution 2.0Å" /> | caption="1euo, resolution 2.0Å" /> | ||
'''Crystal structure of nitrophorin 2 (prolixin-S)'''<br /> | '''Crystal structure of nitrophorin 2 (prolixin-S)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Nitrophorin 2 (NP2) (also known as prolixin-S) is a salivary protein that | + | Nitrophorin 2 (NP2) (also known as prolixin-S) is a salivary protein that transports nitric oxide, binds histamine, and acts as an anticoagulant during blood feeding by the insect Rhodnius prolixus. The 2.0-A crystal structure of NP2 reveals an eight-stranded antiparallel beta-barrel containing a ferric heme coordinated through His(57), similar to the structures of NP1 and NP4. All four Rhodnius nitrophorins transport NO and sequester histamine through heme binding, but only NP2 acts as an anticoagulant. Here, we demonstrate that recombinant NP2, but not recombinant NP1 or NP4, is a potent anticoagulant; recombinant NP3 also displays minor activity. Comparison of the nitrophorin structures suggests that a surface region near the C terminus and the loops between beta strands B-C and E-F is responsible for the anticoagulant activity. NP2 also displays larger NO association rates and smaller dissociation rates than NP1 and NP4, which may result from a more open and more hydrophobic distal pocket, allowing more rapid solvent reorganization on ligand binding. The NP2 protein core differs from NP1 and NP4 in that buried Glu(53), which allows for larger NO release rates when deprotonated, hydrogen bonds to invariant Tyr(81). Surprisingly, this tyrosine lies on the protein surface in NP1 and NP4. |
==About this Structure== | ==About this Structure== | ||
| - | 1EUO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rhodnius_prolixus Rhodnius prolixus] with HEM and NH3 as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1EUO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rhodnius_prolixus Rhodnius prolixus] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=NH3:'>NH3</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1EUO OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Rhodnius prolixus]] | [[Category: Rhodnius prolixus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Andersen, J | + | [[Category: Andersen, J F.]] |
| - | [[Category: Montfort, W | + | [[Category: Montfort, W R.]] |
[[Category: HEM]] | [[Category: HEM]] | ||
[[Category: NH3]] | [[Category: NH3]] | ||
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[[Category: lipocalin]] | [[Category: lipocalin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:31:39 2008'' |
Revision as of 10:31, 21 February 2008
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Crystal structure of nitrophorin 2 (prolixin-S)
Overview
Nitrophorin 2 (NP2) (also known as prolixin-S) is a salivary protein that transports nitric oxide, binds histamine, and acts as an anticoagulant during blood feeding by the insect Rhodnius prolixus. The 2.0-A crystal structure of NP2 reveals an eight-stranded antiparallel beta-barrel containing a ferric heme coordinated through His(57), similar to the structures of NP1 and NP4. All four Rhodnius nitrophorins transport NO and sequester histamine through heme binding, but only NP2 acts as an anticoagulant. Here, we demonstrate that recombinant NP2, but not recombinant NP1 or NP4, is a potent anticoagulant; recombinant NP3 also displays minor activity. Comparison of the nitrophorin structures suggests that a surface region near the C terminus and the loops between beta strands B-C and E-F is responsible for the anticoagulant activity. NP2 also displays larger NO association rates and smaller dissociation rates than NP1 and NP4, which may result from a more open and more hydrophobic distal pocket, allowing more rapid solvent reorganization on ligand binding. The NP2 protein core differs from NP1 and NP4 in that buried Glu(53), which allows for larger NO release rates when deprotonated, hydrogen bonds to invariant Tyr(81). Surprisingly, this tyrosine lies on the protein surface in NP1 and NP4.
About this Structure
1EUO is a Single protein structure of sequence from Rhodnius prolixus with and as ligands. Full crystallographic information is available from OCA.
Reference
The crystal structure of nitrophorin 2. A trifunctional antihemostatic protein from the saliva of Rhodnius prolixus., Andersen JF, Montfort WR, J Biol Chem. 2000 Sep 29;275(39):30496-503. PMID:10884386
Page seeded by OCA on Thu Feb 21 12:31:39 2008
Categories: Rhodnius prolixus | Single protein | Andersen, J F. | Montfort, W R. | HEM | NH3 | Beta barrel | Heme | Lipocalin
