Hemoglobin Roanne [alpha 94(G1) Asp-->Glu]: a variant of the alpha 1 beta 2 interface with an unexpected high oxygen affinity.
In hemoglobin (Hb) Roanne, the aspartate residue alpha 94(G1) is replaced by a glutamic acid. This residue plays a key role in the structural changes affecting the alpha 1 beta 2 contact area during the deoxy- to oxy-state transition in the hemoglobin molecule. Aspartate alpha 94(G1) is involved in several contacts both in the deoxy- and oxy-structures. The most important of those is a hydrogen bond with asparagine beta 102 (G4), stabilizing the oxygenated structure. Alteration of this contact usually leads to a decrease in oxygen affinity. Hb Roanne is the first example in which an increased oxygen affinity was found as a result of a structural modification at this position. Functional data suggested that the mechanisms responsible for this altered property are a destabilisation of the T-structure and a modification of the allosteric equilibrium.
Kister
J
J
INSERM U299, Hôpital de Bicêtre, Le Kremlin Bicêtre, France.
Kiger
L
L
Francina
A
A
Hanny
P
P
Szymanowicz
A
A
Blouquit
Y
Y
Promé
D
D
Galactéros
F
F
Delaunay
J
J
Wajcman
H
H
D000368:Aged; D001224:Aspartic Acid; D001665:Binding Sites; D002248:Carbon Monoxide / Q000378:metabolism; D005260:Female; D018698:Glutamic Acid; D006455:Hemoglobins, Abnormal / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D007525:Isoelectric Focusing; D007700:Kinetics; D013058:Mass Spectrometry; D015394:Molecular Structure; D010100:Oxygen / Q000097:blood*; D013329:Structure-Activity Relationship
D006455:Hemoglobins, Abnormal; C091388:hemoglobin Roanne; D001224:Aspartic Acid; D018698:Glutamic Acid; D002248:Carbon Monoxide; D010100:Oxygen