The dimer-tetramer equilibrium of recombinant hemoglobins. Stabilization of the α1β2 interface by the mutation β(Cys112 → Gly) at the α1β1 interface

Clara Fronticelli, Maurizio Gattoni, A. Lien Lu, William S. Brinigar, Jeffries L.G. Bucci, Emilia Chiancone

Research output: Contribution to journalArticlepeer-review

Abstract

The dimer-tetramer association constants of several recombinant human hemoglobins (in the CO form) have been measured by differential gel filtration. Recombinant human hemoglobin prepared from recombinant β-chains, and mutant hemoglobins where the substitution was on the surface, β(Thr4 → Asp), in the heme pocket, β(Val67 → Thr), at the 2,3-DPG binding site, β(Val1 → Met + His2del), had a twofold smaller association with respect to natural hemoglobin. In a mutant at the α1β21 interface, β(Cys93 → Ala), the association constant was decreased three-fold. Conversely, in a mutant at the α1β1 interface, β(Cys112 → Gly), the association constant was two- and four-fold increased with respect to natural and recombinant human hemoglobin. These differences are energetically very small, consistent with the correct folding of the recombinant hemoglobins. The stabilization of the tetrameric structure by a mutation at the α1β1 interface indicates that structural changes at this interface can be propagated through the protein to the α1β2 interface and, thereby, exert an effect on the allosteric equilibrium.

Original languageEnglish (US)
Pages (from-to)53-57
Number of pages5
JournalBiophysical Chemistry
Volume51
Issue number1
DOIs
StatePublished - Jul 1994
Externally publishedYes

Keywords

  • Differential gel filtration
  • Recombinant hemoglobin
  • Subunit assembly

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Organic Chemistry

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