Enzymes
| UniProtKB help_outline | 3 proteins |
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- Name help_outline Mg-protoporphyrin IX Identifier CHEBI:60492 Charge -2 Formula C34H30MgN4O4 InChIKeyhelp_outline REJJDEGSUOCEEW-RGGAHWMASA-J SMILEShelp_outline CC1=C(CCC([O-])=O)C2=CC3=[N+]4C(=CC5=C(C)C(C=C)=C6C=C7C(C)=C(C=C)C8=[N+]7[Mg--]4(N2C1=C8)N56)C(C)=C3CCC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline S-adenosyl-L-methionine Identifier CHEBI:59789 Charge 1 Formula C15H23N6O5S InChIKeyhelp_outline MEFKEPWMEQBLKI-AIRLBKTGSA-O SMILEShelp_outline C[S+](CC[C@H]([NH3+])C([O-])=O)C[C@H]1O[C@H]([C@H](O)[C@@H]1O)n1cnc2c(N)ncnc12 2D coordinates Mol file for the small molecule Search links Involved in 924 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline Mg-protoporphyrin IX 13-monomethyl ester Identifier CHEBI:60491 Charge -1 Formula C35H33MgN4O4 InChIKeyhelp_outline JHTBRMHXRULRGV-NCCDZXNNSA-L SMILEShelp_outline COC(=O)CCc1c(C)c2C=C3C(C=C)=C(C)C4=[N+]3[Mg--]35n2c1C=C1C(CCC([O-])=O)=C(C)C(C=c2c(C)c(C=C)c(=C4)n32)=[N+]51 2D coordinates Mol file for the small molecule Search links Involved in 5 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline S-adenosyl-L-homocysteine Identifier CHEBI:57856 Charge 0 Formula C14H20N6O5S InChIKeyhelp_outline ZJUKTBDSGOFHSH-WFMPWKQPSA-N SMILEShelp_outline Nc1ncnc2n(cnc12)[C@@H]1O[C@H](CSCC[C@H]([NH3+])C([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 840 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:17809 | RHEA:17810 | RHEA:17811 | RHEA:17812 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Heterologous expression of the bchM gene product from Rhodobacter capsulatus and demonstration that it encodes S-adenosyl-L-methionine:Mg-protoporphyrin IX methyltransferase.
Bollivar D.W., Jiang Z.Y., Bauer C.E., Beale S.I.
The bacteriochlorophyll biosynthesis gene, bchM, from Rhodobacter capsulatus was previously believed to code for a polypeptide involved in formation of the cyclopentone ring of protochlorophyllide from Mg-protoporphyrin IX monomethyl ester. In this study, R. capsulatus bchM was expressed in Escher ... >> More
The bacteriochlorophyll biosynthesis gene, bchM, from Rhodobacter capsulatus was previously believed to code for a polypeptide involved in formation of the cyclopentone ring of protochlorophyllide from Mg-protoporphyrin IX monomethyl ester. In this study, R. capsulatus bchM was expressed in Escherichia coli and the gene product was subsequently demonstrated by enzymatic analysis to catalyze methylation of Mg-protoporphyrin IX to form Mg-protoporphyrin IX monomethyl ester. Activity required the substrates Mg-protoporphyrin IX and S-adenosyl-L-methionine. 14C-labeled product was formed in incubations containing 14C-methyl-labeled S-adenosyl-L-methionine. On the basis of these and previous results, we also conclude that the bchH gene, which was previously reported to code for Mg-protoporphyrin IX methyltransferase, is most likely involved in the Mg chelation step. << Less
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The bacteriochlorophyll biosynthesis gene, bchM, of Rhodobacter sphaeroides encodes S-adenosyl-L-methionine: Mg protoporphyrin IX methyltransferase.
Gibson L.C., Hunter C.N.
The bchM gene of Rhodobacter sphaeroides has been sequenced and then overexpressed in E. coli producing a protein of M(r) approximately. 27,500. Cell-free extracts of the transformed E. coli strain are able to methylate added Mg protoporphyrin, resulting in the formation of Mg protoporphyrin monom ... >> More
The bchM gene of Rhodobacter sphaeroides has been sequenced and then overexpressed in E. coli producing a protein of M(r) approximately. 27,500. Cell-free extracts of the transformed E. coli strain are able to methylate added Mg protoporphyrin, resulting in the formation of Mg protoporphyrin monomethyl ester. The identity of this product was verified by HPLC. The bchM gene product is therefore assigned to the methyltransferase step in bacteriochlorophyll biosynthesis. << Less
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Purification and kinetic characterization of the magnesium protoporphyrin IX methyltransferase from Synechocystis PCC6803.
Shepherd M., Reid J.D., Hunter C.N.
Magnesium protoporphyrin IX methyltransferase (ChlM), catalyses the methylation of magnesium protoporphyrin IX (MgP) at the C(6) propionate side chain to form magnesium protoporphyrin IX monomethylester (MgPME). Threading methods biased by sequence similarity and predicted secondary structure have ... >> More
Magnesium protoporphyrin IX methyltransferase (ChlM), catalyses the methylation of magnesium protoporphyrin IX (MgP) at the C(6) propionate side chain to form magnesium protoporphyrin IX monomethylester (MgPME). Threading methods biased by sequence similarity and predicted secondary structure have been used to assign this enzyme to a particular class of S-adenosyl-L-methionine (SAM)-binding proteins. These searches suggest that ChlM contains a seven-stranded beta-sheet, common among small-molecule methyltransferases. Steady-state kinetic assays were performed using magnesium deuteroporphyrin IX (MgD), a more water-soluble substrate analogue of MgP. Initial rate studies showed that the reaction proceeds via a ternary complex. Product (S-adenosyl-L-homocysteine; SAH) inhibition was used to investigate the kinetic mechanism further. SAH was shown to exhibit competitive inhibition with respect to SAM, and mixed inhibition with respect to MgD. This is indicative of a random binding mechanism, whereby SAH may bind productively to either free enzyme or a ChlM-MgD complex. Our results provide an overview of the steady-state kinetics for this enzyme, which are significant given the role of MgP and MgPME in plastid-to-nucleus signalling and their likely critical role in the regulation of this biosynthetic pathway. << Less