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

Human hemoglobin binds oxygen cooperatively and functions as a tetramer composed of two identical alphabeta 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 (betaE6K) and COHbS (betaE6V) 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 beta6 mutant hemoglobins crystallize (betaK6 > betaV6) as a result of more favorable lattice contacts.

Medienart:

Artikel

Erscheinungsjahr:

2005

Erschienen:

2005

Enthalten in:

Zur Gesamtaufnahme - volume:61

Enthalten in:

Acta crystallographica. Section D, Biological crystallography - 61(2005), Pt 5 vom: 27. Mai, Seite 566-73

Sprache:

Englisch

Beteiligte Personen:

Patskovska, Larysa N [VerfasserIn]
Patskovsky, Yury V [VerfasserIn]
Almo, Steven C [VerfasserIn]
Hirsch, Rhoda Elison [VerfasserIn]

Themen:

3WJQ0SDW1A
9061-29-4
Carboxyhemoglobin
Carboxyhemoglobin, sickle
Hemoglobin, Sickle
Indicators and Reagents
Journal Article
Polyethylene Glycols
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Anmerkungen:

Date Completed 02.08.2005

Date Revised 01.12.2018

published: Print-Electronic

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM155063405