1vpi: Difference between revisions
No edit summary |
No edit summary |
||
| Line 5: | Line 5: | ||
==Overview== | ==Overview== | ||
The high resolution crystal structure of a natural PLA2 inhibitor has been, determined by Patterson search methods. In the heterodimeric, neurotoxic, complex, vipoxin, isolated from the venom of Bulgarian viper, PLA2, inhibitor represents the non-toxic subunit. The model was refined to a, crystallographic R-factor of 15.5% for data between 6 and 1.76 A, resolution. The packing of the inhibitor in the crystal reveals close, contacts between the molecules, which are symmetry-related by the 2-fold, axes of the lattice. These pairs associate as a crystallographic dimer, stabilized by a set of interactions, including van der Waals contacts, between residues from symmetry-related pairs, denoted as the recognition, site and the recognition surface. Residues Ph3, Trp31 and Tyr119 represent, the ... | The high resolution crystal structure of a natural PLA2 inhibitor has been, determined by Patterson search methods. In the heterodimeric, neurotoxic, complex, vipoxin, isolated from the venom of Bulgarian viper, PLA2, inhibitor represents the non-toxic subunit. The model was refined to a, crystallographic R-factor of 15.5% for data between 6 and 1.76 A, resolution. The packing of the inhibitor in the crystal reveals close, contacts between the molecules, which are symmetry-related by the 2-fold, axes of the lattice. These pairs associate as a crystallographic dimer, stabilized by a set of interactions, including van der Waals contacts, between residues from symmetry-related pairs, denoted as the recognition, site and the recognition surface. Residues Ph3, Trp31 and Tyr119 represent, the recognition site of inhibitor which possibly fits to the hydrophobic, wall of the target PLA2. The topology of the inhibitor represents the PLA2, type of folding: three long helices and a beta-hairpin. Superposition of, the structure of the inhibitor shows an almost complete overlap with, different mammalian and viper PLA2 in the backbone and in the position of, the sidechains of the residues that belong to the active centre and the, hydrophobic wall. A "lock and key" mechanism of recognition of its native, PLA2 in gland cells and other toxic PLA2 in vitro has been suggested. The, mechanism includes complementary "head to tail" interactions between the, recognition site of the inhibitor and a recognition surface located on the, hydrophobic wall of the target PLA2. Having a high spatial homology with, the PLA2 family of enzymes but opposing their action, the inhibitor from, vipoxin presents an example of a divergent evolution of an ancient PLA2., The presence of a space for binding calcium in the inhibitor is believed, to be a rudiment and proof of a common origin with PLA2. | ||
==About this Structure== | ==About this Structure== | ||
1VPI is a | 1VPI is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Vipera_ammodytes Vipera ammodytes]. Structure known Active Site: RS. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1VPI OCA]. | ||
==Reference== | ==Reference== | ||
| Line 22: | Line 22: | ||
[[Category: x-ray structure]] | [[Category: x-ray structure]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 12:37:14 2007'' | ||
Revision as of 13:31, 5 November 2007
|
PHOSPHOLIPASE A2 INHIBITOR FROM VIPOXIN
OverviewOverview
The high resolution crystal structure of a natural PLA2 inhibitor has been, determined by Patterson search methods. In the heterodimeric, neurotoxic, complex, vipoxin, isolated from the venom of Bulgarian viper, PLA2, inhibitor represents the non-toxic subunit. The model was refined to a, crystallographic R-factor of 15.5% for data between 6 and 1.76 A, resolution. The packing of the inhibitor in the crystal reveals close, contacts between the molecules, which are symmetry-related by the 2-fold, axes of the lattice. These pairs associate as a crystallographic dimer, stabilized by a set of interactions, including van der Waals contacts, between residues from symmetry-related pairs, denoted as the recognition, site and the recognition surface. Residues Ph3, Trp31 and Tyr119 represent, the recognition site of inhibitor which possibly fits to the hydrophobic, wall of the target PLA2. The topology of the inhibitor represents the PLA2, type of folding: three long helices and a beta-hairpin. Superposition of, the structure of the inhibitor shows an almost complete overlap with, different mammalian and viper PLA2 in the backbone and in the position of, the sidechains of the residues that belong to the active centre and the, hydrophobic wall. A "lock and key" mechanism of recognition of its native, PLA2 in gland cells and other toxic PLA2 in vitro has been suggested. The, mechanism includes complementary "head to tail" interactions between the, recognition site of the inhibitor and a recognition surface located on the, hydrophobic wall of the target PLA2. Having a high spatial homology with, the PLA2 family of enzymes but opposing their action, the inhibitor from, vipoxin presents an example of a divergent evolution of an ancient PLA2., The presence of a space for binding calcium in the inhibitor is believed, to be a rudiment and proof of a common origin with PLA2.
About this StructureAbout this Structure
1VPI is a Single protein structure of sequence from Vipera ammodytes. Structure known Active Site: RS. Full crystallographic information is available from OCA.
ReferenceReference
X-ray structure at 1.76 A resolution of a polypeptide phospholipase A2 inhibitor., Devedjiev Y, Popov A, Atanasov B, Bartunik HD, J Mol Biol. 1997 Feb 14;266(1):160-72. PMID:9054978
Page seeded by OCA on Mon Nov 5 12:37:14 2007