The artificial alpha1beta1-contact mutant hemoglobin, Hb Phe-35beta, shows only small functional abnormalities.
It was previously reported that Hb Philly with a mutation of Phe for Tyr at 35(C1)beta showed non-cooperative oxygen binding with a very high affinity and instability leading to hemolysis. Further, it lacked the 1H-NMR signal at 13.1 ppm from 2,2-dimethyl-2-silapentane-5-sulfonate in normal hemoglobin (Hb A), so that this signal was assigned to a hydrogen bond formed by Tyr-35(C1)beta. Surprisingly, our artificial mutant hemoglobin with the same mutation as Hb Philly showed slightly lowered oxygen affinity, almost normal cooperativity, the 1H-NMR signal at 13.1 ppm and no sign of instability. Our results indicate that the mutation reported for Hb Philly and the assignment of the 13.1 ppm signal need reexamination.
Nakatsukasa
T
T
Division of Biophysical Engineering, Graduate School of Engineering Science, Osaka University, Japan. nakachan@bpe.es.osaka-u.ac.jp
Nomura
N
N
Miyazaki
G
G
Imai
K
K
Wada
Y
Y
Ishimori
K
K
Morishima
I
I
Morimoto
H
H
D019943:Amino Acid Substitution; D001665:Binding Sites; D005914:Globins / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D007700:Kinetics; D046911:Macromolecular Substances; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D010108:Oxyhemoglobins / Q000737:chemistry* / Q000378:metabolism; D010649:Phenylalanine; D017354:Point Mutation; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D014443:Tyrosine
D006454:Hemoglobins; D046911:Macromolecular Substances; D010108:Oxyhemoglobins; D011994:Recombinant Proteins; D014443:Tyrosine; D010649:Phenylalanine; D005914:Globins