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Title: Apo-Nitrophorin 4 at Atomic Resolution

Abstract

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 Angstroms 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.

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
959967
Report Number(s):
BNL-82953-2009-JA
TRN: US201016%%1111
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Protein Science; Journal Volume: 16
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BLOOD; CRYSTAL STRUCTURE; HEME; INSECTS; NITRIC OXIDE; PROTEINS; REMOVAL; RESOLUTION; STABILITY; TRANSPORT; national synchrotron light source

Citation Formats

Amoia,A., and Montfort, W.. Apo-Nitrophorin 4 at Atomic Resolution. United States: N. p., 2007. Web. doi:10.1110/ps.072981907.
Amoia,A., & Montfort, W.. Apo-Nitrophorin 4 at Atomic Resolution. United States. doi:10.1110/ps.072981907.
Amoia,A., and Montfort, W.. Mon . "Apo-Nitrophorin 4 at Atomic Resolution". United States. doi:10.1110/ps.072981907.
@article{osti_959967,
title = {Apo-Nitrophorin 4 at Atomic Resolution},
author = {Amoia,A. and Montfort, W.},
abstractNote = {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 Angstroms 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.},
doi = {10.1110/ps.072981907},
journal = {Protein Science},
number = ,
volume = 16,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}