1u0x

Crystal structure of nitrophorin 4 under pressure of xenon (200 psi)Crystal structure of nitrophorin 4 under pressure of xenon (200 psi)

Structural highlights 1u0x is a 1 chain structure with sequence from Rhopr. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: , , Related: 1d2u, 1koi Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [NP4_RHOPR] Heme-based protein that deliver nitric oxide gas (NO) to the victim while feeding, resulting in vasodilation and inhibition of platelet aggregation. Also bind tightly to histamine, which is released by the host to induce wound healing (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Nitrophorin 4 (NP4) is one of seven nitric oxide (NO) transporting proteins in the blood-sucking insect Rhodnius prolixus. In its physiological function, NO binds to a ferric iron centered in a highly ruffled heme plane. Carbon monoxide (CO) also binds after reduction of the heme iron. Here we have used Fourier transform infrared spectroscopy at cryogenic temperatures to study CO and NO binding and migration in NP4, complemented by x-ray cryo-crystallography on xenon-containing NP4 crystals to identify cavities that may serve as ligand docking sites. Multiple infrared stretching bands of the heme-bound ligands indicate different active site conformations with varying degrees of hydrophobicity. Narrow infrared stretching bands are observed for photodissociated CO and NO; temperature-derivative spectroscopy shows that these bands are associated with ligand docking sites close to the extremely reactive heme iron. No rebinding from distinct secondary sites was detected, although two xenon binding cavities were observed in the x-ray structure. Photolysis studies at approximately 200 K show efficient NO photoproduct formation in the more hydrophilic, open NP4 conformation. This result suggests that ligand escape is facilitated in this conformation, and blockage of the active site by water hinders immediate reassociation of NO to the ferric iron. In the closed, low-pH conformation, ligand escape from the active site of NP4 is prevented by an extremely reactive heme iron and the absence of secondary ligand docking sites. Structural dynamics controls nitric oxide affinity in nitrophorin 4.,Nienhaus K, Maes EM, Weichsel A, Montfort WR, Nienhaus GU J Biol Chem. 2004 Sep 17;279(38):39401-7. Epub 2004 Jul 16. PMID:15258143 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

spinqualitylabelsall models 1u0x, resolution 1.45Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image