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Title: Plant Hemoglobins: A Molecular Fossil Record for the Evolutin of Oxygen Transport

Abstract

The evolution of oxygen transport hemoglobins occurred on at least two independent occasions. The earliest event led to myoglobin and red blood cell hemoglobin in animals. In plants, oxygen transport 'leghemoglobins' evolved much more recently. In both events, pentacoordinate heme sites capable of inert oxygen transfer evolved from hexacoordinate hemoglobins that have unrelated functions. High sequence homology between hexacoordinate and pentacoordinate hemoglobins in plants has poised them for potential structural analysis leading to a molecular understanding of this important evolutionary event. However, the lack of a plant hexacoordinate hemoglobin structure in the exogenously ligand-bound form has prevented such comparison. Here we report the crystal structure of the cyanide-bound hexacoordinate hemoglobin from barley. This presents the first opportunity to examine conformational changes in plant hexacoordinate hemoglobins upon exogenous ligand binding, and reveals structural mechanisms for stabilizing the high-energy pentacoordinate heme conformation critical to the evolution of reversible oxygen binding hemoglobins.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930022
Report Number(s):
BNL-80636-2008-JA
Journal ID: ISSN 0022-2836; JMOBAK; TRN: US200822%%1258
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Molecular Biology; Journal Volume: 371; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANIMALS; BARLEY; BLOOD CELLS; CONFORMATIONAL CHANGES; CRYSTAL STRUCTURE; FOSSILS; FUNCTIONS; HEME; HEMOGLOBIN; LIGANDS; MYOGLOBIN; OXYGEN; PLANTS; national synchrotron light source

Citation Formats

Hoy,J., Robinson, H., Trent, lll, J., Kakar, S., Smagghe, B., and Hargrove, M. Plant Hemoglobins: A Molecular Fossil Record for the Evolutin of Oxygen Transport. United States: N. p., 2007. Web. doi:10.1016/j.jmb.2007.05.029.
Hoy,J., Robinson, H., Trent, lll, J., Kakar, S., Smagghe, B., & Hargrove, M. Plant Hemoglobins: A Molecular Fossil Record for the Evolutin of Oxygen Transport. United States. doi:10.1016/j.jmb.2007.05.029.
Hoy,J., Robinson, H., Trent, lll, J., Kakar, S., Smagghe, B., and Hargrove, M. Mon . "Plant Hemoglobins: A Molecular Fossil Record for the Evolutin of Oxygen Transport". United States. doi:10.1016/j.jmb.2007.05.029.
@article{osti_930022,
title = {Plant Hemoglobins: A Molecular Fossil Record for the Evolutin of Oxygen Transport},
author = {Hoy,J. and Robinson, H. and Trent, lll, J. and Kakar, S. and Smagghe, B. and Hargrove, M.},
abstractNote = {The evolution of oxygen transport hemoglobins occurred on at least two independent occasions. The earliest event led to myoglobin and red blood cell hemoglobin in animals. In plants, oxygen transport 'leghemoglobins' evolved much more recently. In both events, pentacoordinate heme sites capable of inert oxygen transfer evolved from hexacoordinate hemoglobins that have unrelated functions. High sequence homology between hexacoordinate and pentacoordinate hemoglobins in plants has poised them for potential structural analysis leading to a molecular understanding of this important evolutionary event. However, the lack of a plant hexacoordinate hemoglobin structure in the exogenously ligand-bound form has prevented such comparison. Here we report the crystal structure of the cyanide-bound hexacoordinate hemoglobin from barley. This presents the first opportunity to examine conformational changes in plant hexacoordinate hemoglobins upon exogenous ligand binding, and reveals structural mechanisms for stabilizing the high-energy pentacoordinate heme conformation critical to the evolution of reversible oxygen binding hemoglobins.},
doi = {10.1016/j.jmb.2007.05.029},
journal = {Journal of Molecular Biology},
number = 1,
volume = 371,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
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