Control of carbon monoxide binding states and dynamics in hemoglobin I of Lucina pectinata by nearby aromatic residues
| Autor: | Jorge L. Colón, Raul López-Mejía, Angela M. Navarro, Juan López-Garriga, Manuel Maldonado, Juan González-Lagoa |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
education.field_of_study
Population Infrared spectroscopy Inorganic Chemistry chemistry.chemical_compound Crystallography Monomer Myoglobin chemistry Materials Chemistry Organic chemistry Carbon monoxide binding Physical and Theoretical Chemistry education Heme Conformational isomerism Pi backbonding |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 0020-1693 |
| DOI: | 10.1016/0020-1693(95)04903-7 |
| Popis: | The IR spectra of the CO-bound forms of monomeric hemoglobin I (HbI) of Lucina pectinata and of a His64(E7) → Gln64(E7), Leu29(B10) → Phe29(B10), Val68(E11) → Phe68(E11) triple mutant of sperm-whale myoglobin which mimics the heme pocket of HbI, have been measured. HbI shows a main CO stretching component at ν (CO) = 1936 cm −1 , while the triple mutant shows it at ν (CO) = 1935 cm −1 . Both proteins show a larger population of this main A 3 conformer than the A 0 (HbI ν (CO) = 1960 cm −1 , triple mutant ν (CO) = 1961 cm −1 ) or A 1,2 ( ν (CO) = 1950 cm −1 ) conformers when compared to wild-type sperm-whale myoglobin. The preference for the A 3 conformer in these proteins is due to the existence of aromatic phenylalanine residues next to the heme. The positive electric field increase due to nearby phenyl multipoles of the phenylalanines increase backbonding and reduce ν(CO). The synergistic effect of the three unique residues in Lucina pectinata Hb I (His64, Phe29, Phe68) is proposed to control the population of conformational states in this protein and the CO association rate. |
| Databáze: | OpenAIRE |
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