Alteration of the α1 β22 β1 subunit interface contributes to the increased hemoglobinoxygen affinity of high-altitude deer mice

Noriko Inoguchi, Nobuhiro Mizuno, Seiki Baba, Takashi Kumasaka, Chandrasekhar Natarajan, Jay F. Storz, Hideaki Moriyama

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Background Deer mice (Peromyscus maniculatus) that are native to high altitudes in the Rocky Mountains have evolved hemoglobins with an increased oxygen-binding affinity relative to those of lowland conspecifics. To elucidate the molecular mechanisms responsible for the evolved increase in hemoglobin-oxygen affinity, the crystal structure of the highland hemoglobin variant was solved and compared with the previously reported structure for the lowland variant. Results Highland hemoglobin yielded at least two crystal types, in which the longest axes were 507 and 230 Å. Using the smaller unit cell crystal, the structure was solved at 2.2 Å resolution. The asymmetric unit contained two tetrameric hemoglobin molecules. Conclusions The analyses revealed that αPro50 in the highland hemoglobin variant promoted a stable interaction between αHis45 and heme that was not seen in the αHis50 lowland variant. The αPro50 mutation also altered the nature of atomic contacts at the α1 β22 β1 intersubunit interfaces. These results demonstrate how affinity-altering changes in intersubunit interactions can be produced by mutations at structurally remote sites.

Original languageEnglish (US)
Article numbere0174921
JournalPloS one
Issue number3
StatePublished - Mar 2017

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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