Dynamics and reactivity of HbXL99α. A cross-linked hemoglobin derivative

R. W. Larsen, M. D. Chavez, M. R. Ondrias, S. H. Courtney, J. M. Friedman, M. J. Lin, R. E. Hirsch

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Abstract

Resonance Raman spectroscopy, transient absorption, and fluorescence techniques have been employed to investigate the structure and dynamics of the α-cross-linked hemoglobin derivative, HbXL99α. The resonance Raman spectra of the deoxy form of HbXL99α are identical to those of native NbA (ν(Fe-His) ~ 222 cm-1), which exhibit a T-state (low affinity) structure regardless of solvent conditions. The resonance Raman spectra of the transient heme photoproduct resulting from CO photolysis from HbXL99α appear to have structures intermediate between deoxy-T and ligand-bound R structures (ν(Fe-His) ~ 222 cm-1). Time-resolved resonance Raman data of HbXL99α-CO show that complete CO recombination occurs after ~ 5 ms, with only a small amount of the CO-bound species reforming within ~ 200 ns (geminate recombination). Transient absorption spectra of HbXL99α-O2 indicate that the extent of sub-nanosecond geminate recombination of O2 is also reduced in the cross-linked derivative relative to native HbA. The decrease in tryptophan fluorescence of HbXL99α upon oxygenation further indicates that tertiary structural changes at the α12 interface upon ligation are apparently reduced, but not eliminated in the cross-linked derivative relative to HbA.

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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Dynamics and reactivity of HbXL99α. A cross-linked hemoglobin derivative. / Larsen, R. W.; Chavez, M. D.; Ondrias, M. R.; Courtney, S. H.; Friedman, J. M.; Lin, M. J.; Hirsch, R. E.

In: Journal of Biological Chemistry, Vol. 265, No. 8, 30.03.1990, p. 4449-4454.

Research output: Contribution to journalArticle