Abstract
A proton nuclear magnetic resonance study of the reaction of apohemoglobin A with both oxidized and reduced hemes reveals that at least two slowly interconverting species are initially formed, only one of which corresponds to the native proteins. Reconstitutions with isotope-labeled hemes reveal that the hyperfine-shift patterns for heme resonances in the metazido derivatives differ for the two species by interchange of heme environment characteristic of heme orientational disorder about the α,γ-meso axis, as previously demonstrated for myoglobin [La Mar, G. N., Davis, N. L., Parish, D. W., & Smith, K. M. (1983) J. Mol. Biol. 168, 887-896]. Careful scrutiny of the 1H NMR spectrum of freshly prepared hemoglobin A (Hb A) reveals that characteristic resonances for the alternate heme orientation are present in both subunits, clearly demonstrating that "native" Hb A possesses an important structure heterogeneity. It is observed that this heterogeneity disappears with time for one subunit but remains unchanged in the other. This implies that a metastable disordered state in vivo involves the α subunit and an equilibrium disordered state both in vivo and in vitro is involved within the β subunit. The presence of metastable disorder in fresh blood suggests an in vivo hemoglobin assembly from apoprotein and heme that is similar to the in vitro reconstitution process. The slow equilibration and known lifetimes for erythrocytes provide a rationalization for the presence of detectable metastable states. The implications of such heme disorder for Hb function are discussed.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 3826-3831 |
| Number of pages | 6 |
| Journal | Biochemistry |
| Volume | 24 |
| Issue number | 15 |
| State | Published - 1985 |
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- Biochemistry
Cite this
1H NMR characterization of metastable and equilibrium heme orientational heterogeneity in reconstituted and native human hemoglobin. / La Mar, Gerd N.; Yamamoto, Yasuhiko; Jue, Thomas; Smith, Kevin M.; Pandey, Ravindra K.
In: Biochemistry, Vol. 24, No. 15, 1985, p. 3826-3831.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - 1H NMR characterization of metastable and equilibrium heme orientational heterogeneity in reconstituted and native human hemoglobin
AU - La Mar, Gerd N.
AU - Yamamoto, Yasuhiko
AU - Jue, Thomas
AU - Smith, Kevin M.
AU - Pandey, Ravindra K.
PY - 1985
Y1 - 1985
N2 - A proton nuclear magnetic resonance study of the reaction of apohemoglobin A with both oxidized and reduced hemes reveals that at least two slowly interconverting species are initially formed, only one of which corresponds to the native proteins. Reconstitutions with isotope-labeled hemes reveal that the hyperfine-shift patterns for heme resonances in the metazido derivatives differ for the two species by interchange of heme environment characteristic of heme orientational disorder about the α,γ-meso axis, as previously demonstrated for myoglobin [La Mar, G. N., Davis, N. L., Parish, D. W., & Smith, K. M. (1983) J. Mol. Biol. 168, 887-896]. Careful scrutiny of the 1H NMR spectrum of freshly prepared hemoglobin A (Hb A) reveals that characteristic resonances for the alternate heme orientation are present in both subunits, clearly demonstrating that "native" Hb A possesses an important structure heterogeneity. It is observed that this heterogeneity disappears with time for one subunit but remains unchanged in the other. This implies that a metastable disordered state in vivo involves the α subunit and an equilibrium disordered state both in vivo and in vitro is involved within the β subunit. The presence of metastable disorder in fresh blood suggests an in vivo hemoglobin assembly from apoprotein and heme that is similar to the in vitro reconstitution process. The slow equilibration and known lifetimes for erythrocytes provide a rationalization for the presence of detectable metastable states. The implications of such heme disorder for Hb function are discussed.
AB - A proton nuclear magnetic resonance study of the reaction of apohemoglobin A with both oxidized and reduced hemes reveals that at least two slowly interconverting species are initially formed, only one of which corresponds to the native proteins. Reconstitutions with isotope-labeled hemes reveal that the hyperfine-shift patterns for heme resonances in the metazido derivatives differ for the two species by interchange of heme environment characteristic of heme orientational disorder about the α,γ-meso axis, as previously demonstrated for myoglobin [La Mar, G. N., Davis, N. L., Parish, D. W., & Smith, K. M. (1983) J. Mol. Biol. 168, 887-896]. Careful scrutiny of the 1H NMR spectrum of freshly prepared hemoglobin A (Hb A) reveals that characteristic resonances for the alternate heme orientation are present in both subunits, clearly demonstrating that "native" Hb A possesses an important structure heterogeneity. It is observed that this heterogeneity disappears with time for one subunit but remains unchanged in the other. This implies that a metastable disordered state in vivo involves the α subunit and an equilibrium disordered state both in vivo and in vitro is involved within the β subunit. The presence of metastable disorder in fresh blood suggests an in vivo hemoglobin assembly from apoprotein and heme that is similar to the in vitro reconstitution process. The slow equilibration and known lifetimes for erythrocytes provide a rationalization for the presence of detectable metastable states. The implications of such heme disorder for Hb function are discussed.
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M3 - Article
C2 - 4052368
AN - SCOPUS:0022427462
VL - 24
SP - 3826
EP - 3831
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 15
ER -