Hemoglobins Austin and Waco: Two Hemoglobins with substitutions in the α1β2 contact region

Winston F. Moo-Penn, Mary H. Johnson, Katherine C. Bechtel, Danny L. Jue, Bradford L. Therrell, Robert M. Schmidt

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Hemoglobins (Hbs) Austin and Waco were detected by their electrophoretic migration on cellulose acetate (pH 8.4) and citrate agar (pH 6.2). By these methods, both variants migrated between Hbs A and F. Globin chain analysis at pH 8.6 indicated that the mutant β chain of Hb Austin was faster moving than the βA chain; however, the mutant chain of Hb Waco was indistinguishable from the βA chain by this technique. The two variants were isolated by ion-exchange column chromatography. Sequence studies demonstrated a substitution of serine (Hb Austin) and lysine (Hb Waco) for arginine at position 40 in the β chain. These mutations involve an amino acid residue in the α1β2 contact region, which, before this report, had been considered invariant in all hemoglobin sequences. Hb Austin was found to exist as dimers when oxygenated and as tetramers when deoxygenated. The equilibrium constant (Kd) for the tetramer to dimer transition was approximately 300 × 10-6 m, as calculated from sedimentation velocity studies. This variant also had high oxygen affinity, a much reduced heme-heme interaction, and a normal Bohr effect. The functional properties of Hb Waco were similar to those of Hb A.

Original languageEnglish (US)
Pages (from-to)86-94
Number of pages9
JournalArchives of Biochemistry and Biophysics
Volume179
Issue number1
DOIs
StatePublished - Feb 1977
Externally publishedYes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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