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Circular dichroism spectroscopy of Lucina I hemoglobin
Author(s) -
Boffi Alberto,
Wittenberg Jonathan B,
Chiancone Emilia
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00727-8
Subject(s) - heme , chemistry , leghemoglobin , hemeprotein , carbon monoxide , adduct , crystallography , cotton effect , circular dichroism , ferric , hemoglobin , photochemistry , ferrous , stereochemistry , inorganic chemistry , organic chemistry , root nodule , nitrogen fixation , nitrogen , enzyme , catalysis
The monomeric hemoglobin from the mollusc Lucina pectinata (HbI) represents an interesting model system for the study of heme‐related circular dichroic (CD) bands in view of the highly asymmetric distribution of aromatic residues around the heme pocket revealed by the X‐ray crystal structure. The CD spectra of both ferrous and ferric HbI derivatives exhibit negative CD bands in the Soret and ultraviolet region with an enhanced ellipticity of the heme N and L bands in the near‐UV region. In contrast, the magnitude of the Cotton effect in the visible and Soret regions is comparable to that observed in other hemoproteins. The spectrum of the carbon monoxide derivative shows a surprising similarity with that observed for the soybean leghemoglobin carbon monoxide adduct. A common structural feature in the two proteins is the presence in the distal pocket of two Phe residues (B9 and B10) the aromatic rings of which are perpendicular to the heme plane.