2ofm
From Proteopedia
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1.11 A Crystal Structure of Apo Nitrophorin 4 From Rhodnius Prolixus
Overview
The nitrophorins from Rhodnius prolixus, the kissing bug, are, heme-containing proteins used for the transport of nitric oxide to aide, the insect in obtaining a blood meal. The Rhodnius nitrophorins display an, eight-stranded antiparallel beta-barrel motif, typical of lipocalins, with, a histidine-linked heme in the open end of the barrel. Heme is stabilized, in the ferric state and highly distorted, displaying a ruffled, conformation that may be of importance in the setting of the reduction, potential. To help in understanding the means by which the protein matrix, an inherently soft material, is able to distort the heme from its, low-energy planar conformation, we have determined the crystal structure, of apo-nitrophorin 4-1.1 A resolution. Removal of the heme from, nitrophorin 4 has very little effect on its structure: The heme binding, cavity remains open and the loops near the cavity entrance respond to, lower pH in the same manner as the intact protein. We conclude that the, general stability of the lipocalin fold and apparent rigidity of the, beta-barrel provide the means for distorting the heme cofactor.
About this Structure
2OFM is a Single protein structure of sequence from Rhodnius prolixus with as ligand. Full crystallographic information is available from OCA.
Reference
Apo-nitrophorin 4 at atomic resolution., Amoia AM, Montfort WR, Protein Sci. 2007 Sep;16(9):2076-81. Epub 2007 Jul 27. PMID:17660249
Page seeded by OCA on Wed Jan 23 11:33:57 2008
