COHbC and COHbS crystallize in the R2 quaternary state at neutral pH in the presence of PEG 4000

Larysa N. Patskovska, Yury V. Patskovsky, Steven C. Almo, Rhoda Elison Hirsch

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Human hemoglobin binds oxygen cooperatively and functions as a tetramer composed of two identical αβ heterodimers. While human hemoglobin is the best characterized allosteric protein, the quaternary R (oxygenated or liganded) to T (deoxygenated) structural transition remains controversial. The R2 state has been postulated to represent either an intermediate or final quaternary state elicited by ligand binding. However, the biological relevance of the R2 state has been questioned as it has not been observed crystallographically under physiological conditions. The high-resolution R2 quaternary structures of human COHbC (βE6K) and COHbS (βE6V) are reported at neutral pH and low ionic strength using PEG 4000 as a precipitant. Crystals of COHbC, COHbS and their mixtures are isomorphous, indicating that they share the same tertiary and quaternary structures. In contrast, oxyHbA or COHbA did not yield crystals at neutral pH under similar conditions. Solubility studies and modeling suggest that at neutral pH and low ionic strength the β6 mutant hemoglobins crystallize (βK6 > βV6) as a result of more favorable lattice contacts.

Original languageEnglish (US)
Pages (from-to)566-573
Number of pages8
JournalActa Crystallographica Section D: Biological Crystallography
Volume61
Issue number5
DOIs
StatePublished - May 2005

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hemoglobin
Polyethylene glycols
Hemoglobins
Ionic strength
Osmolar Concentration
Crystals
Solubility
crystals
solubility
Oxygen
Ligands
proteins
ligands
high resolution
oxygen
Proteins

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Biophysics
  • Condensed Matter Physics
  • Structural Biology

Cite this

COHbC and COHbS crystallize in the R2 quaternary state at neutral pH in the presence of PEG 4000. / Patskovska, Larysa N.; Patskovsky, Yury V.; Almo, Steven C.; Hirsch, Rhoda Elison.

In: Acta Crystallographica Section D: Biological Crystallography, Vol. 61, No. 5, 05.2005, p. 566-573.

Research output: Contribution to journalArticle

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