This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1eqd
From Proteopedia
|
CRYSTAL STRUCTURE OF NITROPHORIN 4 COMPLEXED WITH CN
Overview
The nitrophorins comprise an unusual family of proteins that use ferric, (Fe(III)) heme to transport highly reactive nitric oxide (NO) from the, salivary gland of a blood sucking bug to the victim, resulting in, vasodilation and reduced blood coagulation. We have determined structures, of nitrophorin 4 in complexes with H2O, cyanide and nitric oxide. These, structures reveal a remarkable feature: the nitrophorins have a broadly, open distal pocket in the absence of NO, but upon NO binding, three or, more water molecules are expelled and two loops fold into the distal, pocket, resulting in the packing of hydrophobic groups around the NO, molecule and increased distortion of the heme. In this way, the protein, apparently forms a 'hydrophobic trap' for the NO molecule. The structures, are very accurate, ranging between 1.6 and 1.4 A resolutions.
About this Structure
1EQD is a Single protein structure of sequence from Rhodnius prolixus with CYN, HEV and CIT as ligands. Full crystallographic information is available from OCA.
Reference
Nitric oxide binding to nitrophorin 4 induces complete distal pocket burial., Weichsel A, Andersen JF, Roberts SA, Montfort WR, Nat Struct Biol. 2000 Jul;7(7):551-4. PMID:10876239
Page seeded by OCA on Tue Nov 20 14:13:43 2007
Categories: Rhodnius prolixus | Single protein | Andersen, J.F. | Montfort, W.R. | Roberts, S.A. | Weichsel, A. | CIT | CYN | HEV | Beta barrel | Cyanide | Ferric heme | Lipocalin fold
