Abstract

A Hb from the chloroplast of Chlamydomonas eugametos has been cloned andexpressed in E. coli. This Hb resembles several invetebrate in having a tyr residue in the B10 and a glut in the E7 positions, both of which are believed to participate in H-bonding to bound O2 that results in extremely slow off-rates. On the other hand, Chlamydomonas Hb is unusual in that the ferrous protein has a high-spin to low spin (six-coordinate) transition pK of 8.5, whereas the ferric protein has a high-spin to low spin (six-coordinate) transition pK of 6.4. This suggests that the distal ligand of the low spin forms of the ferrous and the ferric proteins may be different. The ferric protein exhibits a single low spin form with g values of 2.52, 2.31, 1.86, and thus an anisotropy similar to that of myoglobin hydroxide. However, 17O EPR and 18O resonance Raman studies failed to provide direct evidence for a hydroxide ligand. Spectroscopic studies on the distal mutants of the B10 Tyr, E7 Gln, and the E10 Lys residues have so far failed to identify a possible amino acid ligand. Further studies are being conducted to identify the distal ligand and to understand the unusual low spin EPR spectrum.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
3P41RR002583-13S1
Application #
6121166
Study Section
Project Start
1998-05-05
Project End
2000-04-30
Budget Start
1998-10-01
Budget End
1999-09-30
Support Year
13
Fiscal Year
1999
Total Cost
Indirect Cost

  Institution

Name
Albert Einstein College of Medicine
Department
Type
DUNS #
009095365
City
Bronx
State
NY
Country
United States
Zip Code
10461

  Publications

Colaneri, M J; Vitali, J; Peisach, J (2000) Electron spin-echo envelope modulation study of multicrystalline Cu(2+)-insulin: effects of Cd(2+) on the nuclear quadrupole interaction of the Cu(2+)-coordinated imidazole remote nitrogen. Biochemistry 39:584-91
Lee, H C; Goroncy, A K; Peisach, J et al. (2000) Demonstration of a conserved histidine and two water ligands at the Mn2+ site in Diocleinae lectins by pulsed EPR spectroscopy. Biochemistry 39:2340-6
Sam, J W; Takahashi, S; Lippai, I et al. (1998) Sequence-specific changes in the metal site of ferric bleomycin induced by the binding of DNA. J Biol Chem 273:16090-7
Magliozzo, R S; Marcinkeviciene, J A (1997) The role of Mn(II)-peroxidase activity of mycobacterial catalase-peroxidase in activation of the antibiotic isoniazid. J Biol Chem 272:8867-70
Nersissian, A M; Mehrabian, Z B; Nalbandyan, R M et al. (1996) Cloning, expression, and spectroscopic characterization of Cucumis sativus stellacyanin in its nonglycosylated form. Protein Sci 5:2184-92
Gasdaska, J R; Law, J H; Bender, C J et al. (1996) Cockroach transferrin closely resembles vertebrate transferrins in its metal ion-binding properties: a spectroscopic study. J Inorg Biochem 64:247-58
Tipton, P A; Quinn, T P; Peisach, J et al. (1996) Role of the divalent metal ion in the NAD:malic enzyme reaction: an ESEEM determination of the ground state conformation of malate in the E:Mn:malate complex. Protein Sci 5:1648-54
Coffino, A R; Peisach, J (1996) Simulation of Mn (II) EPR spectra using a full spin-Hamiltonian approach. J Magn Reson B 111:127-34
Magliozzo, R S; Bubacco, L; McCracken, J et al. (1995) Cu(II) coordination in arthropod and mollusk green half-methemocyanins analyzed by electron spin-echo envelope modulation spectroscopy. Biochemistry 34:1513-23
Marcinkeviciene, J A; Magliozzo, R S; Blanchard, J S (1995) Purification and characterization of the Mycobacterium smegmatis catalase-peroxidase involved in isoniazid activation. J Biol Chem 270:22290-5

Showing the most recent 10 out of 41 publications