Difference Fourier Transform Infrared Evidence for Ester Bonds Linking the Heme Group in Myeloperoxidase, Lactoperoxidase, and Eosinophil Peroxidase

Kooter, Ingeborg M.; Pierik, Antonio J.; Merkx, Maarten; Averill, Bruce A.; Moguilevsky, Nicole; Bollen, A.; Wever, Ron

doi:10.1021/ja9725460

Cited by 53 publications

(55 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…19 Esters have two characteristic strong absorptions arising from the C=O usually found in the range of 1800-1650 cm -1 . 20 The FT-IR spectrum of the citric acid and glycerol mixtures, before and after of the heating had absorption bands in the region of 1728 cm -1 ( Figure 2S(c), supplementary Figure 2S(d), supplementary material), respectively, related to the stretching vibration of the C=O bond of the ester-group. These absorption peaks were not observed in the spectra of glycerol ( Figure 2S(a), supplementary material) while the spectra of the citric acid ( Figure 2S(b), supplementary material) presented two absorption peaks related to the vibration of the C=O bond of aliphatic carboxylic acid, at 1702 and 1747 cm -1 .…”

Section: Fourier Transform Infrared (Ft-ir) Spectroscopymentioning

confidence: 99%

Citric acid as multifunctional agent in blowing films of starch/PBAT

Garcia¹,

Grossmann²,

Yamashita³

et al. 2011

Quím. Nova

View full text Add to dashboard Cite

Recebido em 20/10/10; aceito em 14/4/11; publicado na web em 10/6/11Citric acid was used as a compatibilizer in the production of starch and PBAT films plasticized with glycerol and processed by blow extrusion. Films produced were characterized by WVP, mechanical properties, FT-IR-ATR and SEM. WPV ranged from 3.71 to 12.73×10 -11 g m -1 s -1 Pa -1, while tensile strength and elongation at break ranged from 1.81 to 7.15 MPa and from 8.61 to 23.63%, respectively. Increasing the citric acid concentration improved WVP and slightly decreased film resistance and elongation. The films micrographs revealed a more homogeneous material with the addition of citric acid. However, the infrared spectra revealed little about cross-linking esterification reaction.

show abstract

Section: Fourier Transform Infrared (Ft-ir) Spectroscopymentioning

confidence: 99%

Citric acid as multifunctional agent in blowing films of starch/PBAT

Garcia¹,

Grossmann²,

Yamashita³

et al. 2011

Quím. Nova

View full text Add to dashboard Cite

show abstract

“…Two ester bonds were claimed to be present, between modified methyl groups on pyrrole rings A and C and the amino acids Glu 242 and Asp 94 . In a recent study, we have provided the first direct evidence by FTIR difference spectroscopy that ester bonds link the heme groups in all mammalian peroxidases via the conserved aspartate and glutamate residues (14). The third linkage involves the nonconserved Met 243 residue, for which there is considerable evidence.…”

mentioning

confidence: 99%

“…Therefore reduced oxidized spectra of a labeled recombinant MPO are recorded. In a previous FTIR study this detection method has allowed us to identify specific ester bonds sensitive to the oxidation state of the enzyme (14). Fig.…”

mentioning

confidence: 99%

The Sulfonium Ion Linkage in Myeloperoxidase

Kooter¹,

Moguilevsky²,

Bollen³

et al. 1999

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

The heme group of myeloperoxidase is covalently linked via two ester bonds to the protein and a unique sulfonium ion linkage involving Met 243 . Mutation of Met 243 into Thr, Gln, and Val, which are the corresponding residues of eosinophil peroxidase, lactoperoxidase, and thyroid peroxidase, respectively, and into Cys was performed. The Soret band in the optical absorbance spectrum in the oxidized mutants is now found at approximately 411 nm. Both the pyridine hemochrome spectra and resonance Raman spectra of the mutants are affected by the mutation. In the Met 243 mutants the affinity for chloride has decreased 100-fold. All mutants have lost their chlorination activity, except for the M243T mutant, which still has 15% activity left. By Fourier transform infared difference spectroscopy it was possible to specifically detect the 13 CD 3 -labeled methionyl sulfonium ion linkage. We conclude that the sulfonium ion linkage serves two roles. First, it serves as an electron-withdrawing substituent via its positive charge, and, second, together with its neighboring residue Glu 242 , it appears to be responsible for the lower symmetry of the heme group and distortion from the planar conformation normally seen in heme-containing proteins.In the family of mammalian peroxidases, myeloperoxidase (MPO) 1 is an extraordinary peroxidase. First of all, the enzyme is the only mammalian peroxidase known to peroxidize chloride to hypochlorous acid at a substantial rate. Secondly, MPO differs in its spectroscopic characteristics by its unusual redshifted Soret band in the optical absorbance as well in its pyridine hemochrome spectrum, its complicated resonance Raman spectrum, and its inverted sign pattern of the Soret band in the MCD spectrum (1-6). Those differences have been attributed to the special nature or structure of the heme group in MPO. Because this heme is covalently bound to the protein, characterization of this chromophore has been difficult. Based on different spectroscopic techniques, a formyl-containing heme a, a chlorin, and a heme b prosthetic group have been proposed in the past (3,5,(7)(8)(9).Although the enzyme differs in spectroscopic and catalytic properties, the homology between MPO and the other mammalian peroxidases is high. MPO shares respectively 70, 61, and 47% identical residues with eosinophil peroxidase (EPO), lactoperoxidase (LPO), and thyroid peroxidase (TPO) (10 -12), and an even higher homology can be found among the residues in the active site. MPO is the only mammalian peroxidase for which a crystal structure is known, at 2.3 Å resolution (13). The structural data for human MPO suggested that three heme substituents form covalent bonds with amino acid side chains in the protein. Two ester bonds were claimed to be present, between modified methyl groups on pyrrole rings A and C and the amino acids Glu 242 and Asp 94 . In a recent study, we have provided the first direct evidence by FTIR difference spectroscopy that ester bonds link the heme groups in all mammalian peroxidases via the conser...

show abstract

“…Nevertheless, it has been unambiguously demonstrated that the ester covalent links are formed via an autocatalytic mechanism (12). It has also been shown in MPO that only a carboxylate can trigger covalent tethering of the heme to the protein (13), and in LPO that the length of the carboxylate side chain is critical for the same bond to be formed (2).…”

mentioning

confidence: 99%

Horseradish Peroxidase Mutants That Autocatalytically Modify Their Prosthetic Heme Group

Colas

Montellano

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

The mammalian peroxidases, including myeloperoxidase and lactoperoxidase, bind their prosthetic heme covalently through ester bonds to two of the heme methyl groups. These bonds are autocatalytically formed. No other peroxidase is known to form such bonds. To determine whether features other than an appropriately placed carboxylic acid residue are important for covalent heme binding, we have introduced aspartate and/or glutamic acid residues into horseradish peroxidase, a plant enzyme that exhibits essentially no sequence identity with the mammalian peroxidases. Based on superposition of the horseradish peroxidase and myeloperoxidase structures, the mutated residues were Leu 37 , Phe 41 , Gly 69 , and Ser 73 . The F41E mutant was isolated with no covalently bound heme, but the heme was completely covalently bound upon incubation with H 2 O 2 . As predicted, the modified heme released from the protein was 3-hydroxymethylheme. The S73E mutant did not covalently bind its heme but oxidized it to the 8-hydroxymethyl derivative. The hydroxyl group in this modified heme derived from the medium. The other mutations gave unstable proteins. The rate of compound I formation for the F41E mutant was 100 times faster after covalent bond formation, but the reduction of compound I to compound II was similar with and without the covalent bond. The results clearly establish that an appropriately situated carboxylic acid group is sufficient for covalent heme attachment, strengthen the proposed mechanism, and suggest that covalent heme attachment in the mammalian peroxidases relates to peroxidase biology or stability rather than to intrinsic catalytic properties.Mammalian peroxidases share a unique feature, the formation of two or three covalent bonds to their prosthetic heme 1 group, not found in the peroxidases of other organisms. The two common bonds in all mammalian peroxidases are ester links between a conserved glutamate and aspartate and the heme 1-methyl and 5-methyl substituents, respectively. In MPO a third bond is forged between a methionine and the ␤ carbon of the 2-vinyl substituent (1). Mutagenesis studies with LPO have demonstrated that at least one of the two ester bonds is required for catalytic activity (2). Interestingly, a single covalent link between the heme and protein is also found in most members of the CYP4A, -4B, and -4F classes of cytochrome P450 enzymes (3-7). In contrast to LPO, however, mutagenesis studies show that the heme-protein covalent bond is not essential for the catalytic activity of at least some of these P450 enzymes (8, 6). A long known example of heme covalent binding is provided by cytochrome c, in which a cysteine residue is covalently bound to each of the two porphyrin vinyl groups. Although many hypotheses have been formulated concerning the functional advantages of the links in cytochrome c, including bending of the heme, increasing the heme affinity (9), and increasing the stability of the methionyl-Fe(II) coordination (10), the question has yet to be definitively answered.Despite m...

show abstract

Difference Fourier Transform Infrared Evidence for Ester Bonds Linking the Heme Group in Myeloperoxidase, Lactoperoxidase, and Eosinophil Peroxidase

Cited by 53 publications

References 33 publications

Citric acid as multifunctional agent in blowing films of starch/PBAT

Citric acid as multifunctional agent in blowing films of starch/PBAT

The Sulfonium Ion Linkage in Myeloperoxidase

Horseradish Peroxidase Mutants That Autocatalytically Modify Their Prosthetic Heme Group

Contact Info

Product

Resources

About