Overproduction of α chains provides a proton-insensitive component to the bluefish hemoglobin system

Celia Bonaventura, Gerald Godette, Robert Stevens, Michael Brenowitz, Robert Henkens

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Expression of α and β chains and their post-translational assembly into α2β2 tetramers is fundamental to the formation and function of most vertebrate hemoglobins. There is a strong evolutionary bias that favors expression of equal amounts of the two types of chains, because coopexrativity, pH sensitivity, and anionic control of function occurs only for the α2β2 tetramers. Remarkably, an overproduction of α chains, as in the pathological condition known as β thalassemia in humans, is adaptive rather than pathological in the bluefish hemoglobin system. The thalassemia of the bluefish is a novel means of providing for oxygen uptake and delivery when low pH conditions incapacitate the highly pH-sensitive Root effect hemoglobins of the fish. Although fish often have pH-insensitive along with highly pH-sensitive hemoglobins, having pH-insensitive α chain monomers in circulation is an unusual structural variation. The role of bluefish α chains in oxygen transport is enabled by their remarkably lower oxygen affinity relative to human α chains. This is the first reported case of a thalassemic condition that is maintained in a species as an adaptive advantage.

Original languageEnglish (US)
Pages (from-to)40509-40514
Number of pages6
JournalJournal of Biological Chemistry
Volume280
Issue number49
DOIs
StatePublished - Dec 9 2005

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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