Enzymes
UniProtKB help_outline | 1 proteins |
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- Name help_outline ATP Identifier CHEBI:30616 (Beilstein: 3581767) help_outline Charge -4 Formula C10H12N5O13P3 InChIKeyhelp_outline ZKHQWZAMYRWXGA-KQYNXXCUSA-J SMILEShelp_outline Nc1ncnc2n(cnc12)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 1,280 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2O Identifier CHEBI:15377 (Beilstein: 3587155; CAS: 7732-18-5) help_outline Charge 0 Formula H2O InChIKeyhelp_outline XLYOFNOQVPJJNP-UHFFFAOYSA-N SMILEShelp_outline [H]O[H] 2D coordinates Mol file for the small molecule Search links Involved in 6,204 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline Mg2+ Identifier CHEBI:18420 (CAS: 22537-22-0) help_outline Charge 2 Formula Mg InChIKeyhelp_outline JLVVSXFLKOJNIY-UHFFFAOYSA-N SMILEShelp_outline [Mg++] 2D coordinates Mol file for the small molecule Search links Involved in 8 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline protoporphyrin IX Identifier CHEBI:57306 (Beilstein: 3897489,9313467) help_outline Charge -2 Formula C34H32N4O4 InChIKeyhelp_outline KSFOVUSSGSKXFI-UJJXFSCMSA-L SMILEShelp_outline Cc1c(CCC([O-])=O)c2cc3[nH]c(cc4nc(cc5[nH]c(cc1n2)c(C)c5C=C)c(C)c4C=C)c(C)c3CCC([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 9 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline ADP Identifier CHEBI:456216 (Beilstein: 3783669) help_outline Charge -3 Formula C10H12N5O10P2 InChIKeyhelp_outline XTWYTFMLZFPYCI-KQYNXXCUSA-K SMILEShelp_outline Nc1ncnc2n(cnc12)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 841 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- 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 phosphate Identifier CHEBI:43474 Charge -2 Formula HO4P InChIKeyhelp_outline NBIIXXVUZAFLBC-UHFFFAOYSA-L SMILEShelp_outline OP([O-])([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 992 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:13961 | RHEA:13962 | RHEA:13963 | RHEA:13964 | |
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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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Interplay between an AAA module and an integrin I domain may regulate the function of magnesium chelatase.
Fodje M.N., Hansson A., Hansson M., Olsen J.G., Gough S., Willows R.D., Al-Karadaghi S.
In chlorophyll biosynthesis, insertion of Mg(2+) into protoporphyrin IX is catalysed in an ATP-dependent reaction by a three-subunit (BchI, BchD and BchH) enzyme magnesium chelatase. In this work we present the three-dimensional structure of the ATP-binding subunit BchI. The structure has been sol ... >> More
In chlorophyll biosynthesis, insertion of Mg(2+) into protoporphyrin IX is catalysed in an ATP-dependent reaction by a three-subunit (BchI, BchD and BchH) enzyme magnesium chelatase. In this work we present the three-dimensional structure of the ATP-binding subunit BchI. The structure has been solved by the multiple wavelength anomalous dispersion method and refined at 2.1 A resolution to the crystallographic R-factor of 22.2 % (R(free)=24.5 %). It belongs to the chaperone-like "ATPase associated with a variety of cellular activities" (AAA) family of ATPases, with a novel arrangement of domains: the C-terminal helical domain is located behind the nucleotide-binding site, while in other known AAA module structures it is located on the top. Examination by electron microscopy of BchI solutions in the presence of ATP demonstrated that BchI, like other AAA proteins, forms oligomeric ring structures. Analysis of the amino acid sequence of subunit BchD revealed an AAA module at the N-terminal portion of the sequence and an integrin I domain at the C terminus. An acidic, proline-rich region linking these two domains is suggested to contribute to the association of BchI and BchD by binding to a positively charged cleft at the surface of the nucleotide-binding domain of BchI. Analysis of the amino acid sequences of BchI and BchH revealed integrin I domain-binding sequence motifs. These are proposed to bind the integrin I domain of BchD during the functional cycle of magnesium chelatase, linking porphyrin metallation by BchH to ATP hydrolysis by BchI. An integrin I domain and an acidic and proline-rich region have been identified in subunit CobT of cobalt chelatase, clearly demonstrating its homology to BchD. These findings, for the first time, provide an insight into the subunit organisation of magnesium chelatase and the homologous colbalt chelatase. << Less
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Mechanism and regulation of Mg-chelatase.
Walker C.J., Willows R.D.
Mg-chelatase catalyses the insertion of Mg into protoporphyrin IX (Proto). This seemingly simple reaction also is potentially one of the most interesting and crucial steps in the (bacterio)chlorophyll (Bchl/Chl)-synthesis pathway, owing to its position at the branch-point between haem and Bchl/Chl ... >> More
Mg-chelatase catalyses the insertion of Mg into protoporphyrin IX (Proto). This seemingly simple reaction also is potentially one of the most interesting and crucial steps in the (bacterio)chlorophyll (Bchl/Chl)-synthesis pathway, owing to its position at the branch-point between haem and Bchl/Chl synthesis. Up until the level of Proto, haem and Bchl/Chl synthesis share a common pathway. However, at the point of metal-ion insertion there are two choices: Mg2+ insertion to make Bchl/Chl (catalysed by Mg-chelatase) or Fe2+ insertion to make haem (catalysed by ferrochelatase). Thus the relative activities of Mg-chelatase and ferrochelatase must be regulated with respect to the organism's requirements for these end products. How is this regulation achieved? For Mg-chelatase, the recent design of an in vitro assay combined with the identification of Bchl-biosynthetic enzyme genes has now made it possible to address this question. In all photosynthetic organisms studied to date, Mg-chelatase is a three-component enzyme, and in several species these proteins have been cloned and expressed in an active form. The reaction takes place in two steps, with an ATP-dependent activation followed by an ATP-dependent chelation step. The activation step may be the key to regulation, although variations in subunit levels during diurnal growth may also play a role in determining the flux through the Bchl/Chl and haem branches of the pathway. << Less