Optical spectroscopic observation of a metastable form of sperm whale myoglobin generated by reconstitution

Gebe, J.A.; Peyton, David H.; Peyton, J.A.

doi:10.1016/0006-291x(89)91594-5

Cited by 9 publications

(4 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The spectra in Figure 5A demonstrate the time dependence for the Soret region from the reconstitution of SnPP into apoEqMb; Figure 5B shows difference spectra for this reaction. This result is reminiscent of the optical spectra obtained for the reconstitution of heme into apoSwMb (Gebe et al, 1989). In that case, however, the initially observed species wás a 1:1 mixture of heme-insertion isomers (Jue et al, 1983), while here the initially observed species is not a mixture, at least as we can detect by NMR.…”

Section: Resultssupporting

confidence: 75%

Proton NMR study of the interaction of tin(IV) protoporphyrin IX monomers and dimers with apomyoglobin

Deeb¹,

Peyton²

1992

Biochemistry

View full text Add to dashboard Cite

Events during the reconstitution of apomyoglobin to form the holoprotein were probed by porphyrin-metal substitution. Thus interactions between tin(IV) protoporphyrin IX (SnPP) and equine apomyoglobin (apoEqMb), and between tin(IV) protoporphyrin IX dimers [(SnPP)2] and apoEqMb, were observed by 1H NMR and optical absorbance spectroscopic techniques. The chief advantages of using SnPP are that products and intermediates can easily be related to SnPP.EqMb which has been studied [Deeb, R.S., & Peyton, D.H. (1991) J. Biol. Chem. 266, 3728-3733] and that at least one step during reconstitution is slowed considerably as compared to heme. Reactions of apoEqMb with SnPP and (SnPP)2 produce different intermediates, although the final product, SnPP.EqMb, is the same for each. An intermediate observed for reaction of SnPP with apoEqMb at pH 10 is in exchange with free SnPP, with the observed rate constant koff approximately 1 s-1. meso-Proton resonances were assigned for this intermediate by correlation to SnPP resonances via chemical exchange. The intermediate observed for reaction of (SnPP)2 with apoEqMb at pH 7.5 is heterogeneous. The reaction of either SnPP or (SnPP)2 with apoEqMb at neutral pH produces another species which may be the alternate porphyrin-insertion isomer arising from a 180 degree rotation about the alpha, gamma-meso axis of the porphyrin. Although optical absorbance spectroscopy of the Soret region shows evidence for each reaction, only in combination with 1H NMR are the various processes assigned.

show abstract

Section: Resultssupporting

confidence: 75%

Proton NMR study of the interaction of tin(IV) protoporphyrin IX monomers and dimers with apomyoglobin

Deeb¹,

Peyton²

1992

Biochemistry

View full text Add to dashboard Cite

show abstract

“…A small change occurs in the 450-650 nm region of the optical spectrum when the reconstitution is perfonned with SnPP (Figure 30), during the 파ne frame that SnPP.EqMb' disappe따s from Figure 24. A similar result has been found for FePPIX (Gebe et al, 1989) and attributed formation and subsequent redisσibution of hemin-insertion isomers. DiFeo and Addison (1991) reached a similar conclusion for iron porphyrin-globin complexes, that Q-band splitting does not arise from hemeinsertion isomers in that system.…”

supporting

confidence: 72%

Nuclear Magnetic Resonance Investigation of the Interaction of Heme Binding Proteins with SnIVprotoporphyrin IX and Heme: Structure and Conformational Changes of Myoglobin and Hemopexin

Deeb

2000

View full text Add to dashboard Cite

“…Furthermore, minimal imidazole ring bond rotations are adequate to dissociate the imidazole from the iron, causing bond breakage and minimal imidazole ring bond rotations are also sufficient to reassociate the imidazole back to the iron and re-forming the bond [53], although this depends on the orientation of the haem [54]. This means that the distal histidine constantly moves towards and away from the haem, which recombines rapidly with the globin [55][56][57]. What Hargove [33] did provide was similar data obtained at 424 nm, in which the transients were clearly at least biphasic, and a simulation of these using the same rate constants and unpublished extinction coefficients for two of the three forms of the protein in (6) and (7).…”

Section: Regulation Of O 2 Binding To Haemoglobinsmentioning

confidence: 99%

The structure and function of mammalian and plant globins

Brown

Yow

2013

Scie

View full text Add to dashboard Cite

Globins are haemoproteins such as haemoglobin (Hb), myoglobin (Mb), cytoglobin (Cb), neuroglobin (Nb), leghaemoglobin (LHb) and non-symbiotic Hb (NsHb). While the monomers of these six proteins have the characteristic '3-on-3' α-helical sandwich tertiary structure and there are similarities in their patterns of secondary structure, they have poor primary sequence homology. Moreover, they differ in quaternary structure and in the coordination of the haem, three (Hb, Mb, LHb) being 5-coordinate and Cb, Nb and NsHb being 6-coordinate. Despite this, each of these globins binds small ligands, such as O 2 , CO and NO, in the sixth position, which implies that it must be possible to displace the imidazole occupying that position in Cb, Nb and NsHb. In addition to O 2 binding, globins are variously involved in O 2 sensing and NO detoxification, and act as an NO dioxygenase. These functions can generate the oxidised (or met-) form of the globin, which may be reduced by a globin reductase. In the case of Hb two globin reductases have been characterised: a nonenzymatic reduction by cytochrome b 5 , which is enzymatically reduced by NADH:cytochrome b 5 reductase, and an NADPH:flavin reductase.Scientia -Vol. 124 -The structure and function of mammalian and plant globins 1 . Introduction.Humans and other vertebrates have at least four globins: (i) an α 2 β 2 tetrameric haemoglobin (Hb) in erythrocytes; (ii) a monomeric myoglobin (Mb) in smooth and skeletal muscle [1, 2]; (iii) a homotetrameric neuroglobin (Nb) in neural tissues [3][4][5][6][7] ; and (iv) a homodimeric cytoglobin (Cb) in almost every tissue, including muscle and neural tissues [8, 9]. Two globins have been identified in plant tissues: (i) leghaemoglobin (LHb) in the nodules of legumes and (ii) non-symbiotic Hb (NsHb) in stressed and metabolically active tissues in species of non-legumes ranging from Arabidopsis thaliana to Oryza sativa [10][11][12]. The subunits of these six proteins are structurally similar, although their primary sequences are not especially well conserved. The monomer of each has a single polypeptide chain enclosing the haem between the layers of a 'three-on-three' α-helical sandwich. Each of these globins is involved in (i) ligand binding (especially O 2 , but other ligands such as NO, CO and CN are also important), (ii) O 2 concentration sensing, (iii) the detoxification of NO and (iv) acting as an NO dioxygenase. Here, we review the structure and function of these globins and the significance of and evidence for the globin reductases. . Molecular structure. 2.1 . The prosthetic group.The globins of many multicellular organisms contain protoporphyrin IX [13,14], although some have no haem [15] and others have a modified haem [16,17]. The porphyrin has a conjugated double ring system: an outer ring of 20 carbon atoms and an inner ring of 16 atoms (including 4 nitrogen atoms). The outer and inner rings are linked by four methene bridges. The inner ring contributes the majority of the delocalised π bonding system (18 electrons compared with ...

show abstract

Optical spectroscopic observation of a metastable form of sperm whale myoglobin generated by reconstitution

Cited by 9 publications

References 14 publications

Proton NMR study of the interaction of tin(IV) protoporphyrin IX monomers and dimers with apomyoglobin

Proton NMR study of the interaction of tin(IV) protoporphyrin IX monomers and dimers with apomyoglobin

Nuclear Magnetic Resonance Investigation of the Interaction of Heme Binding Proteins with SnIVprotoporphyrin IX and Heme: Structure and Conformational Changes of Myoglobin and Hemopexin

The structure and function of mammalian and plant globins

Contact Info

Product

Resources

About