scholarly journals Familial secondary erythrocytosis due to increased oxygen affinity is caused by destabilization of the T state of hemoglobin Brigham (α2β2Pro100Leu)

2012 ◽  
Vol 21 (10) ◽  
pp. 1444-1455 ◽  
Author(s):  
Todd L. Mollan ◽  
Bindu Abraham ◽  
Michael Brad Strader ◽  
Yiping Jia ◽  
Jay N. Lozier ◽  
...  
Keyword(s):  
Oxygen Affinity ◽  
T State

Cross-linking with O-raffinose lowers oxygen affinity and stabilizes haemoglobin in a non-cooperative T-state conformation

2005 ◽  
Vol 385 (3) ◽  
pp. 839-839
Author(s):  
Y. JIA ◽  
S. RAMASAMY ◽  
F. WOOD ◽  
A. I. ALAYASH ◽  
J. M. RIFKIND
Keyword(s):  
Oxygen Affinity ◽  
Cross Linking ◽  
T State

Structure and Oxygen Affinity of Crystalline of DesArg141α Human Hemoglobin A in the T State

1995 ◽  
Vol 248 (1) ◽  
pp. 136-150 ◽  
Author(s):  
Jeffrey S. Kavanaugh ◽  
David R. Chafin ◽  
Arthur Arnone ◽  
Andrea Mozzarelli ◽  
Claudio Rivetti ◽  
...  
Keyword(s):  
Oxygen Affinity ◽  
Human Hemoglobin ◽  
Hemoglobin A ◽  
T State

scholarly journals Structure and Oxygen Affinity of Crystalline des-His-146β Human Hemoglobin in the T State

1997 ◽  
Vol 272 (52) ◽  
pp. 33077-33084 ◽  
Author(s):  
Stefano Bettati ◽  
Laura D. Kwiatkowski ◽  
Jeffrey S. Kavanaugh ◽  
Andrea Mozzarelli ◽  
Arthur Arnone ◽  
...  
Keyword(s):  
Oxygen Affinity ◽  
Human Hemoglobin ◽  
T State

Structures of R- and T-state hemoglobin Bassett: elucidating the structural basis for the low oxygen affinity of a mutant hemoglobin

2005 ◽  
Vol 61 (2) ◽  
pp. 156-162 ◽  
Author(s):  
Martin K. Safo ◽  
Osheiza Abdulmalik ◽  
Hsiang-Ru Lin ◽  
Toshio Asakura ◽  
Donald J. Abraham
Keyword(s):  
Oxygen Affinity ◽  
Structural Basis ◽  
Low Oxygen ◽  
T State ◽  
Low Oxygen Affinity

scholarly journals Organotin-protein interactions. Binding of triethyltin bromide to cat haemoglobin

1986 ◽  
Vol 233 (2) ◽  
pp. 471-477 ◽  
Author(s):  
K R Siebenlist ◽  
F Taketa
Keyword(s):  
Protein Binding ◽  
Protein Interactions ◽  
Three Dimensional ◽  
Oxygen Affinity ◽  
Inositol Hexaphosphate ◽  
Histidine Residues ◽  
Affinity Constants ◽  
Alpha Globin ◽  
Three Dimensional Configuration ◽  
T State

Triethyltin binds to native cat and rat haemoglobin but not to their denatured forms or to other animal haemoglobins. Two molecules of the organotin bind to one molecule of R-state cat haemoglobin with affinity constants of about 1 × 105 M-1. Little or no triethyltin is bound to the deoxygenated (T-state) protein. Binding appears to be dependent upon the existence of a specific three-dimensional configuration of cysteine and histidine residues. The properties of the triethyltin-cat haemoglobin complex are consistent with those of a haemoglobin conformer whose allosteric equilibrium is displaced toward the R-state. Its oxygen affinity and rate of oxidation by nitrite is increased, and the rate of reduction of the methaemoglobin derivative by ascorbate is decreased. These effects of triethyltin are opposite and antagonistic to the effects of inositol hexaphosphate. They are exerted on the alpha- as well as beta-haem groups, even though triethyltin is bound at sites on alpha-globin far removed from the haem groups.

scholarly journals Structure of liganded T-state haemoglobin from cat (Felis silvestris catus), a low oxygen-affinity species, in two different crystal forms

2014 ◽  
Vol 70 (7) ◽  
pp. 1898-1906 ◽  
Author(s):  
Moovarkumudalvan Balasubramanian ◽  
Ponnuraj Sathya Moorthy ◽  
Kamariah Neelagandan ◽  
Ramya Ramadoss ◽  
Prasanna R. Kolatkar ◽  
...  
Keyword(s):  
Mammalian Species ◽  
Oxygen Affinity ◽  
Structural Features ◽  
Low Oxygen ◽  
Felis Silvestris Catus ◽  
Binding Properties ◽  
Crystal Forms ◽  
Allosteric Effectors ◽  
T State ◽  
Low Oxygen Affinity

Haemoglobin (Hb) is an iron-containing metalloprotein which plays a major role in the transportation of oxygen from the lungs to tissues and of carbon dioxide back to the lungs. Hb is in equilibrium between low-affinity tense (T) and high-affinity relaxed (R) states associated with its unliganded and liganded forms, respectively. Mammalian species can be classified into two groups on the basis of whether they express `high' or `low' oxygen-affinity Hbs. Although Hbs from the former group have been studied extensively, a more limited number of structural studies have been performed for low oxygen-affinity Hbs. Here, the crystal structure of low oxygen-affinity cat methaemoglobin (metHb) has been solved at 2.0 and 2.4 Å resolution in two different crystal forms. Even though both structures are fully liganded, they unusually adopt a T-state-like quaternary conformation but with several localized R-like tertiary-structural and quaternary-structural features. The study provides atomic-level insights into the ligand-binding properties of this Hb, including its low cooperativity, blunt response to allosteric effectors and low affinity for oxygen, as well as further contributing to the mechanism underlying Hb allostery.

scholarly journals Cross-linking with O-raffinose lowers oxygen affinity and stabilizes haemoglobin in a non-cooperative T-state conformation

2004 ◽  
Vol 384 (2) ◽  
pp. 367-375 ◽  
Author(s):  
Yiping JIA ◽  
Somasundaram RAMASAMY ◽  
Francine WOOD ◽  
Abdu I. ALAYASH ◽  
Joseph M. RIFKIND
Keyword(s):  
Hyperfine Splitting ◽  
Oxygen Affinity ◽  
Thiol Group ◽  
Cross Linking ◽  
Native Protein ◽  
Epr Spectrum ◽  
Human Haemoglobin ◽  
Lower Oxygen ◽  
T State ◽  
Kinetics Of

O-R-polyHbA0 is an intra- and intermolecularly O-raffinose cross-linked derivative of deoxygenated human haemoglobin developed as an oxygen therapeutic. When compared with its native protein (HbA0), O-R-polyHbA0 was found to be locked in the T (tense) quaternary conformation with a lower oxygen affinity, a reduced Bohr effect (50% of HbA0) and no measurable cooperativity (h=1). The kinetics of oxygen and CO binding to the protein indicate lower ‘on’ rates and faster ‘off’ rates than HbA0 and the absence of effects of inositol hexaphosphate (IHP) on the kinetics. Other properties consistent with a T-like conformation are inaccessibility of the βCys-93 thiol group of O-R-polyHbA0, the hyperfine splitting from nitrogen in the EPR spectrum of the Fe(II)NO complex of O-R-polyHbA0 and decreased flexibility in the distal haem pocket, as indicated by low-spin bis-histidine complexes detected by EPR of oxidized chains. A comparison of the properties of O-R-polyHbA0 with those of HbA0 with and without IHP, as well as the reaction of nitrite with deoxygenated haemoglobin, provide additional insights into the variations in the conformation of T-state haemoglobin in solution (modifications of the T state produced by adding organic phosphates, like IHP and 2,3-diphosphoglycerate). Although the physiological ramifications of locking HbA0 in the T conformation with the O-raffinose are still unknown, valuable insights into haemoglobin function are provided by these studies of O-R-polyHbA0.

scholarly journals High and low oxygen affinity conformations of T state hemoglobin

2008 ◽  
Vol 10 (11) ◽  
pp. 2401-2407 ◽  
Author(s):  
Stefano Bruno ◽  
Maria Bonaccio ◽  
Stefano Bettati ◽  
Claudio Rivetti ◽  
Cristiano Viappiani ◽  
...  
Keyword(s):  
Oxygen Affinity ◽  
Low Oxygen ◽  
T State ◽  
Low Oxygen Affinity
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