| First Author | Igarashi J | Year | 2003 |
| Journal | Biochim Biophys Acta | Volume | 1650 |
| Issue | 1-2 | Pages | 99-104 |
| PubMed ID | 12922173 | Mgi Jnum | J:85037 |
| Mgi Id | MGI:2671549 | Doi | 10.1016/s1570-9639(03)00205-x |
| Citation | Igarashi J, et al. (2003) CO binding study of mouse heme-regulated eIF-2alpha kinase: kinetics and resonance Raman spectra. Biochim Biophys Acta 1650(1-2):99-104 |
| abstractText | Heme-regulated eukaryotic initiation factor (eIF)-2alpha kinase (HRI) regulates the synthesis of globin chains in reticulocytes with heme availability. In the present study, CO binding kinetics to the 6-coordinated Fe(II) heme of the amino-terminal domain of mouse HRI and resonance Raman spectra of the Fe(II)-CO complex are examined to probe the character of the heme environment. The CO association rate constant, k(on)', and CO dissociation rate constant, k(off), were 0.0029 microM(-1)s(-1) and 0.003 s(-1), respectively. These values are very slow compared with those of mouse neuroglobin and sperm whale myoglobin, while the k(off) value of HRI was close to those of the 6-coordinated hemoglobins from Chlamydomonas and barley (0.0022 and 0.0011 s(-1)). The dissociation rate constant of an endogenous ligand, which occurs prior to CO association, was 18.3 s(-1), which was lower than those (197 and 47 s(-1)) of the same 6-coordinated hemoglobins. Resonance Raman spectra suggest that the Fe-C-O adopts an almost linear and upright structure and that the bound CO interacts only weakly with nearby amino acid residues. |
