Non-site-specific allosteric effect of oxygen on human hemoglobin under high oxygen partial pressure

Masayoshi Takayanagi, Ikuo Kurisaki, Masataka Nagaoka*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Protein allostery is essential for vital activities. Allosteric regulation of human hemoglobin (HbA) with two quaternary states T and R has been a paradigm of allosteric structural regulation of proteins. It is widely accepted that oxygen molecules (O2) act as a ''site-specific'' homotropic effector, or the successive O2 binding to the heme brings about the quaternary regulation. However, here we show that the site-specific allosteric effect is not necessarily only a unique mechanism of O2 allostery. Our simulation results revealed that the solution environment of high O2 partial pressure enhances the quaternary change from T to R without binding to the heme, suggesting an additional ''non-site-specific'' allosteric effect of O2. The latter effect should play a complementary role in the quaternary change by affecting the intersubunit contacts. This analysis must become a milestone in comprehensive understanding of the allosteric regulation of HbA from the molecular point of view.

Original languageEnglish
Article number04601
JournalScientific reports
Volume3
DOIs
Publication statusPublished - 2014 Apr 8
Externally publishedYes

ASJC Scopus subject areas

  • General

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