Band 3 catalyzes sickle hemoglobin polymerization

Maria A. Rotter, Haiyan Chu, Philip S. Low, Frank A. Ferrone

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

We have measured homogeneous and heterogeneous nucleation rates of sickle hemoglobin (HbS) in the presence of a strongly binding deletion mutant of the cytoplasmic domain of band 3 (cdb3), a membrane protein known to form dimers and to bind 2 HbS molecules to such a dimer, and we find that it accelerated both rates by a factor of 2. A weakly binding mutant, in contrast showed no impact on nucleation rates, contrary to naïve expectations of a slight enhancement based on the molecular crowding of the solution by the mutant. We find we can explain these phenomena by a model of HbS-cdb3 interaction in which the strong binding mutant, by stabilizing an HbS dimer, catalyzes the nucleation process, while the weak mutant binds only 1 HbS molecule, effectively inactivating it and thereby compensating for the crowding of the solution by the cdb3. The catalytic behavior we observe could play a role in intracellular processes.

Original languageEnglish (US)
Pages (from-to)55-59
Number of pages5
JournalBiophysical Chemistry
Volume146
Issue number2-3
DOIs
StatePublished - Feb 2010

Keywords

  • Band 3
  • Catalysis
  • Molecular crowding
  • Nucleation
  • Red cell membrane
  • Sickle hemoglobin

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Organic Chemistry

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