Orientation of the heme vinyl groups in the hydrogen sulfide-binding hemoglobin I from Lucina pectinata
Eilyn Silfa 1, Maritza Almeida 1, Jose Cerda 1, Shaoxiong Wu 2, Juan López-Garriga 1 *
1Chemistry Department, University of Puerto Rico, PO Box 9019, Mayagüez, Puerto Rico 00680
2Department of Chemistry, Emory University, Atlanta, Georgia 30322
Abstrac
| Hemoglobin I (HbI) from the claim Lucina pectinata is a unique heme protein that binds and transfers hydrogen sulfide (H2S) to a symbiotic bacteria. The metcyano, metaquo, carbon monoxy, oxy, and deoxy complexes of HbI were studied by resonance Raman (RR) spectroscopy, and the metcyano and carbon monoxy complexes were also studied by 1H-NMR. The results indicate a unique orientation of the heme 2-vinyl group relative to other heme proteins. The RR spectra of the HbICO, metHbICN, metHbIH2O, HbIO2 and deoxyHbI heme derivatives show a band at 1621 cm-1 and a shoulder at 1626 cm-1, indicative of an out-of-plane position for one of the vinyls relative to the other one. Spin-lattice relaxation properties of protons in the metHbICN complex also suggest a unique orientation for the heme 2-vinyl group of HbI. The longitudinal relaxation time (T1) for the 2-H, 2-Hc, and Ht protons are 120 ms, 115 ms, and 135 ms, respectively. The data from both techniques suggest an out-of-plane and trans-oriented 2-vinyl group, and an in-plane and cis-oriented 4-vinyl group for the low-spin complexes of HbI. These results imply that the electron withdrawing character of the out-of-plane vinyl group contributes to the stability of the heme Fe+3 oxidation state, facilitates the binding of the H2S ligand, and promotes the stability of this ferric H2S complex. © 1998 John Wiley & Sons, Inc. Biospectroscopy 4: 311-326, 1998 |
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nulla. In hac habitasse platea dictumst. Nulla nonummy. Cras quis libero.
Cras venenatis. Aliquam posuere lobortis pede. Nullam fringilla urna id leo.
Praesent aliquet pretium erat. Praesent non odio. Pellentesque a magna a
mauris vulputate lacinia. Aenean viverra. Class aptent taciti sociosqu ad
litora torquent per conubia nostra, per inceptos hymenaeos. Aliquam lacus.
Mauris magna eros, semper a, tempor et, rutrum et, tortor.
Story Title
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec molestie.
Sed aliquam sem ut arcu. Phasellus sollicitudin. Vestibulum condimentum facilisis
nulla. In hac habitasse platea dictumst. Nulla nonummy. Cras quis libero.
Cras venenatis. Aliquam posuere lobortis pede. Nullam fringilla urna id leo.
Praesent aliquet pretium erat. Praesent non odio. Pellentesque a magna a
mauris vulputate lacinia. Aenean viverra. Class aptent taciti sociosqu ad
litora torquent per conubia nostra, per inceptos hymenaeos. Aliquam lacus.
Mauris magna eros, semper a, tempor et, rutrum et, tortor.
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec molestie.
Sed aliquam sem ut arcu. Phasellus sollicitudin. Vestibulum condimentum facilisis
nulla. In hac habitasse platea dictumst. Nulla nonummy. Cras quis libero.
Cras venenatis. Aliquam posuere lobortis pede. Nullam fringilla urna id leo.
Praesent aliquet pretium erat. Praesent non odio. Pellentesque a magna a
mauris vulputate lacinia. Aenean viverra. Class aptent taciti sociosqu ad
litora torquent per conubia nostra, per inceptos hymenaeos. Aliquam lacus.
Mauris magna eros, semper a, tempor et, rutrum et, tortor.
