Structure and ligand selection of hemoglobin II from Lucina pectinata.
Enviado por Carmen Lydia Cadilla el
Título | Structure and ligand selection of hemoglobin II from Lucina pectinata. |
Publication Type | Journal Article |
Year of Publication | 2008 |
Autores | Gavira, JA, Camara-Artigas, A, De Jesús-Bonilla, W, López-Garriga, J, Lewis, A, Pietri, R, Yeh, S-R, Cadilla, C, García-Ruiz, JManuel |
Journal | J Biol Chem |
Volume | 283 |
Issue | 14 |
Pagination | 9414-23 |
Date Published | 2008 Apr 4 |
ISSN | 0021-9258 |
Palabras clave | Animals, Bivalvia, Crystallography, X-Ray, Dimerization, Heme, Hemoglobins, Hydrogen Bonding, Oxygen, Spectrum Analysis, Raman, Structural Homology, Protein, Sulfites, Water |
Abstract | Lucina pectinata ctenidia harbor three heme proteins: sulfide-reactive hemoglobin I (HbI(Lp)) and the oxygen transporting hemoglobins II and III (HbII(Lp) and HbIII(Lp)) that remain unaffected by the presence of H(2)S. The mechanisms used by these three proteins for their function, including ligand control, remain unknown. The crystal structure of oxygen-bound HbII(Lp) shows a dimeric oxyHbII(Lp) where oxygen is tightly anchored to the heme through hydrogen bonds with Tyr(30)(B10) and Gln(65)(E7). The heme group is buried farther within HbII(Lp) than in HbI(Lp). The proximal His(97)(F8) is hydrogen bonded to a water molecule, which interacts electrostatically with a propionate group, resulting in a Fe-His vibration at 211 cm(-1). The combined effects of the HbII(Lp) small heme pocket, the hydrogen bonding network, the His(97) trans-effect, and the orientation of the oxygen molecule confer stability to the oxy-HbII(Lp) complex. Oxidation of HbI(Lp) Phe(B10) --> Tyr and HbII(Lp) only occurs when the pH is decreased from pH 7.5 to 5.0. Structural and resonance Raman spectroscopy studies suggest that HbII(Lp) oxygen binding and transport to the host bacteria may be regulated by the dynamic displacements of the Gln(65)(E7) and Tyr(30)(B10) pair toward the heme to protect it from changes in the heme oxidation state from Fe(II) to Fe(III). |
DOI | 10.1074/jbc.M705026200 |
Alternate Journal | J. Biol. Chem. |
PubMed ID | 18203714 |
PubMed Central ID | PMC2431033 |
Grant List | G12 RR 03051 / RR / NCRR NIH HHS / United States G12 RR003051 / RR / NCRR NIH HHS / United States HL 65465 / HL / NHLBI NIH HHS / United States P20 RR 016470 / RR / NCRR NIH HHS / United States S06 GM 08103-34 / GM / NIGMS NIH HHS / United States |