Hemoglobin tarrant: α126(rmH) Asp a ̊ Asn. A new hemoglobin variant in the α1β1 contact region showing high oxygen affinity and reduced cooperativity

Winston F. Moo-Penn, Danny L. Jue, Mary H. Johnson, Sylvia M. Wilson, Bradford Therrell, Robert M. Schmidt

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Hemoglobin (Hb) Tarrant was detected by its electrophoretic mobility on cellulose acetate (pH 8.4) and citrate agar (pH 6.2). On cellulose acetate it moved as a band between hemoglobins F and S, and on citrate agar as a band at hemoglobin S. The test for solubility in 2 M phosphate buffer with Na2S2O4 was negative. The new variant has a substitution of asparagine for aspartic acid in position 126 of the α-chain, one of the sites involved in the α1β1 contact. Furthermore, in deoxyhemoglobin aspartic acid 126 of each α chain also forms a non-covalent electrostatic salt bridge with arginine 141 of the corresponding α chain (Perutz, M. F. and Ten Eyck, L. F. (1972) Cold Spring Harbor Symp. Quant. Biol. 36, 295-310 and Perutz, M. F. (1970) Nature 228, 726-739). As a consequence of this substitution in hemoglobin Tarrant, the deoxy conformation or T state is destabilized because these two bridges cannot be formed. This condition is reflected in high oxygen affinity and low cooperativity.

Original languageEnglish (US)
Pages (from-to)443-451
Number of pages9
JournalBBA - Protein Structure
Volume490
Issue number2
DOIs
StatePublished - Feb 22 1977

ASJC Scopus subject areas

  • Medicine(all)

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