Ligand‐induced reversal of the Soret CD band of lamprey hemoglobin

Lampe, Jed N.; Rein, H.; Scheler, W

doi:10.1016/0014-5793(72)80362-4

Cited by 10 publications

(4 citation statements)

References 11 publications

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“…Lamprey Hb shows a negative Soret Cotton effect and this can become positive when nitrosobenzene or alkyl isocyanides are bound. All of these curves are of about the same order of magnitude (Lampe et al, 1972). It is apparent therefore that fairly subtle changes can cause the negative By component to be larger than the positive Bx component.…”

Section: Discussionmentioning

confidence: 80%

Circular dichroism studies of myoglobin and leghemoglobin

Nicola¹,

Minasian²,

Appleby³

et al. 1975

Biochemistry

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The circular dichroism spectra of leghemoglobin a from the root nodules of soybean have been compared with those for sperm whale myoglobin in the fat- and near-ultraviolet and the Soret and visible regions of the spectrum. Circular dichroism spectra in the far-ultraviolet show that the leghemoglobins all have a high alpha-helix content (soybean leghemoglobin a, 55%) regardless of the nature of bound ligands and oxidation or spin state of the heme iron. The known sequence homologies with mammalian hemoglobins may therefore be reflected in conformational homologies as suggested by the x-ray studies of Vainshtein et al. ((1975) Nature (London) 254, 163-164) on lupin leghemoglobin. Removal of the heme moiety decreases helicity by only 9% for leghemoglobins, compared with 23% for myoglobin. This, the much smaller heme contribution to the near-ultraviolet circular dichroism than in myoglobin, and the greater accessibility of the heme moiety to aqueous solvent (Nicola et al. (1974), Proc. Aust. Biochem. Soc. 7, 21) suggest that the association between heme and protein is much weaker in leghemoglobins than in myoglobin. The aromatic Soret and visible circular dichroism spectra for all derivatives of leghemoglobin are opposite in sense to those for myoglobin, showing that the patterns of protein side chain contacts with the heme are different in the two classes of heme proteins. There is strong evidence that one of the two tryptophans whose identity and structural role in myoglobin is known, is present also in plant leghemoglobins, hydrogen-bonded and in a similar nonpolar environment whether heme is present or not. The above findings help to explain the remarkably high oxygen affinity and some other ligand-binding properties of leghemoglobins which differ from those of myoglobin.

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Section: Discussionmentioning

confidence: 80%

Circular dichroism studies of myoglobin and leghemoglobin

Nicola¹,

Minasian²,

Appleby³

et al. 1975

Biochemistry

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“…Studies of' the binding of small molecules to haem proteins to elucidate the factors that govern haem reactivity have been the effort of many groups (Smith & Williams, 1968;Lampe et al, 1972;Appleby et al, 1973;Beetlestone et al, 1976;Addison & Stephanos, 1986;Rohlfs et al, 1988). Beetlestone et al (1976) attributed the lower azide affinity of Hbm (compared with that for a typical mammalian methaemoglobin) to the close proximity of the iron atom to an aspartic acid residue.…”

Section: Azide Bindingmentioning

confidence: 99%

“…bands reflects the conclusion of earlier studies on lamprey haemoglobin, which showed ligand-induced reversal of the Soret c.d. band (Lampe et al, 1972). Still another group concluded that for reversed orientation in spermwhale myoglobin there appears to be almost complete cancellation of the rotational strengths arising from interactions between 7T--w* transitions of the haem group and aromatic amino acid residues (Light et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

Haem-binding-site heterogeneity and haem Cotton effects of Glycera dibranchiata monomeric haemoglobins

Difeo

Addison

1989

Biochemical Journal

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The five major components of the monomeric haemoglobin from Glycera dibranchiata were separated and characterized by absorption spectroscopy, isoelectric focusing, azide-binding affinities and nitrosyl autoreduction kinetics. The differences found among the components are discussed in terms of haem-pocket variations. In addition, the Fourier-transform i.r. spectra of pooled monomeric haemoglobin carbonyl (HbmCO) and the major component carbonyl are reported. The c.d. spectra of the carbonyl and azide derivatives of the five components are compared and found to be similar. The c.d. spectra of myoglobin(II) carbonyl [Mb(II)CO] and of apomyoglobin (apoMb) reconstituted with a symmetric synthetic iron porphyrin carbonyl, meso-tetra-(p-carboxyphenyl)porphinatoiron(II) carbonyl [TCPPFe(II)CO], are compared with the c.d. spectra of pooled HbmCO and its TCPPFe(II)CO analogue. HbmTCPPFe(II)CO shows a negative Soret c.d. band whereas MbTCPPFe(II)CO produces both a negative and a positive Soret c.d. band. Displacement of the symmetric porphyrin by 8-anilinonaphthalene-1-sulphonate and the resulting fluorescence emission are reported.

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“…Similarly, JRP-u shows a negative Soret extremum in the re-duced form (19). It appears that this behaviour is a common property of plant peroxidases, whereas it had also been noted for some other hemoproteins such as lamprey hemoglobin (31) and erythrocruorin (27). This effect may be related to a significant reorientation of the heme transition moments (32,33) and (or) to a conformational change leading to a displacement of aromatic side chains in the heme environment.…”

Section: Discussionmentioning

confidence: 71%

Circular dichroism of turnip peroxidases

Job¹,

Dunford²

1977

Can. J. Biochem.

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Circular dichroic (CD) spectra of two turnip isoperoxidases, P1 and P7, and of their derivatives were measured over the wavelength range of 200 to 650 nm. For the two isoenzymes, it was observed that although the visible and Soret bands are located at similar wavelengths, their ellipticities are different. These results suggest that the active sites are similar but that differences do exist. The results are compared with those reported for Japanese radish peroxidase a and horseradish peroxidase. It appears that a common property of plant peroxidases is the presence of negative CD Soret bands for the reduced forms and their inversion upon cyanide binding. The CD spectra in the far UV region indicate an appreciable helical content for both native enzymes and their various derivatives. The calculated contents of unordered structure are very high (greater than 50% for either P1 or P7), in agreement with other studies on glycoproteins.

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Ligand‐induced reversal of the Soret CD band of lamprey hemoglobin

Cited by 10 publications

References 11 publications

Circular dichroism studies of myoglobin and leghemoglobin

Circular dichroism studies of myoglobin and leghemoglobin

Haem-binding-site heterogeneity and haem Cotton effects of Glycera dibranchiata monomeric haemoglobins

Circular dichroism of turnip peroxidases

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