skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Enhanced polymerization of recombinant human deoxyhemoglobin. beta. 6 Glu yields Ile

Abstract

Polymerization of the deoxy form of sickle cell hemoglobin involves both hydrophobic and electrostatic intermolecular contacts. These interactions drive the mutated molecules into long fibrous rods composed of seven pairs of strands. X-ray crystallography of Hb S and electron microscopy image reconstruction of the fibers have revealed the remarkable complementarity between one of the {beta}6 valines of each molecule (the donor site) and an acceptor site at the EF corner of a neighboring tetramer. To estimate the relative importance of this key hydrophobic contact in polymer formation the authors have generated a polymerizing Hb with isoleucine at the {beta}6 position ({beta}E6I) by site-directed mutagenesis. The mutated {beta} chains were produced in Escherichia coli and reassembled into functional tetramers with native {alpha} chains. Compared to native Hb S, the {beta}E6I mutant polymerizes faster and with a shortened delay time in 1.8 M phosphate buffer, indicating an increased stability of the nuclei preceding fiber growth. Computer modeling of the donor-acceptor interaction shows that the presence of an isoleucine side chain at the donor site induced increased contacts with the receptor site and an increased buried surface area, in agreement with the higher hydrophobicity of the isoleucine residue. The agreement between the predictedmore » and experimental differences in solubility suggests that the transfer of the {beta}6 valine or isoleucine side chain from water to a hydrophobic environment is sufficient to explain the observations.« less

Authors:
; ; ; ; ; ;  [1]; ;  [2]
  1. National de la Sante et de la Recherche Medicale (France)
  2. Faculte des Sciences II, Geneva (Switzerland)
Publication Date:
OSTI Identifier:
6215525
Resource Type:
Journal Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America; (USA)
Additional Journal Information:
Journal Volume: 87:5; Journal ID: ISSN 0027-8424
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; HEMOGLOBIN; PROTEIN ENGINEERING; STRUCTURE-ACTIVITY RELATIONSHIPS; BIOCHEMICAL REACTION KINETICS; CRYSTALLOGRAPHY; ESCHERICHIA COLI; GLUTAMIC ACID; LEUCINE; LIGANDS; X-RAY DIFFRACTION; AMINO ACIDS; BACTERIA; CARBOXYLIC ACIDS; COHERENT SCATTERING; DIFFRACTION; GLOBINS; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; KINETICS; MICROORGANISMS; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PIGMENTS; PORPHYRINS; PROTEINS; REACTION KINETICS; SCATTERING; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Baudin-Chich, V, Pagnier, J, Marden, M, Bohn, B, Lacaze, N, Kister, J, Poyart, C, Schaad, O, and Edelstein, S J. Enhanced polymerization of recombinant human deoxyhemoglobin. beta. 6 Glu yields Ile. United States: N. p., 1990. Web. doi:10.1073/pnas.87.5.1845.
Baudin-Chich, V, Pagnier, J, Marden, M, Bohn, B, Lacaze, N, Kister, J, Poyart, C, Schaad, O, & Edelstein, S J. Enhanced polymerization of recombinant human deoxyhemoglobin. beta. 6 Glu yields Ile. United States. https://doi.org/10.1073/pnas.87.5.1845
Baudin-Chich, V, Pagnier, J, Marden, M, Bohn, B, Lacaze, N, Kister, J, Poyart, C, Schaad, O, and Edelstein, S J. 1990. "Enhanced polymerization of recombinant human deoxyhemoglobin. beta. 6 Glu yields Ile". United States. https://doi.org/10.1073/pnas.87.5.1845.
@article{osti_6215525,
title = {Enhanced polymerization of recombinant human deoxyhemoglobin. beta. 6 Glu yields Ile},
author = {Baudin-Chich, V and Pagnier, J and Marden, M and Bohn, B and Lacaze, N and Kister, J and Poyart, C and Schaad, O and Edelstein, S J},
abstractNote = {Polymerization of the deoxy form of sickle cell hemoglobin involves both hydrophobic and electrostatic intermolecular contacts. These interactions drive the mutated molecules into long fibrous rods composed of seven pairs of strands. X-ray crystallography of Hb S and electron microscopy image reconstruction of the fibers have revealed the remarkable complementarity between one of the {beta}6 valines of each molecule (the donor site) and an acceptor site at the EF corner of a neighboring tetramer. To estimate the relative importance of this key hydrophobic contact in polymer formation the authors have generated a polymerizing Hb with isoleucine at the {beta}6 position ({beta}E6I) by site-directed mutagenesis. The mutated {beta} chains were produced in Escherichia coli and reassembled into functional tetramers with native {alpha} chains. Compared to native Hb S, the {beta}E6I mutant polymerizes faster and with a shortened delay time in 1.8 M phosphate buffer, indicating an increased stability of the nuclei preceding fiber growth. Computer modeling of the donor-acceptor interaction shows that the presence of an isoleucine side chain at the donor site induced increased contacts with the receptor site and an increased buried surface area, in agreement with the higher hydrophobicity of the isoleucine residue. The agreement between the predicted and experimental differences in solubility suggests that the transfer of the {beta}6 valine or isoleucine side chain from water to a hydrophobic environment is sufficient to explain the observations.},
doi = {10.1073/pnas.87.5.1845},
url = {https://www.osti.gov/biblio/6215525}, journal = {Proceedings of the National Academy of Sciences of the United States of America; (USA)},
issn = {0027-8424},
number = ,
volume = 87:5,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 1990},
month = {Thu Mar 01 00:00:00 EST 1990}
}