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

Journal Article (Journal Article)

Expression of alpha and beta chains and their post-translational assembly into alpha(2)beta(2) 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 cooperativity, pH sensitivity, and anionic control of function occurs only for the alpha(2)beta(2) tetramers. Remarkably, an over-production of alpha chains, as in the pathological condition known as beta 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 alpha chain monomers in circulation is an unusual structural variation. The role of bluefish alpha chains in oxygen transport is enabled by their remarkably lower oxygen affinity relative to human alpha chains. This is the first reported case of a thalassemic condition that is maintained in a species as an adaptive advantage.

Full Text

Duke Authors

Cited Authors

  • Bonaventura, C; Godette, G; Stevens, R; Brenowitz, M; Henkens, R

Published Date

  • December 9, 2005

Published In

Volume / Issue

  • 280 / 49

Start / End Page

  • 40509 - 40514

PubMed ID

  • 16166086

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M505353200


  • eng

Conference Location

  • United States