Part:BBa_K1080011
ChlI2
Magnesium chelatase subunit I - The second gene which catalyzes the insertion of magnesium ion into protoporphyrin IX to yield Mg-protoporphyrin IX. Forms an ATP dependent hexameric ring complex and a complex with the ChlD subunit.
Usage and Biology
The chelation of magnesium in protoporphyrin IX is dependant on several genes. These include ChlI, ChlD, ChlH and GUN4. According to previous research, the ChlI component of this pathway proves essential in the chelation of magnesium. The ChlI gene encodes 2 isoforms, ChlI1 and ChlI2. The already familiar function of ChlI1 is well known and documented. The second isoform, ChlI2 is also integral in magnesium chelation complementing ChlI1 [http://www.plantphysiol.org/content/150/2/636.full]
Figure 1: Reaction catalysed by Mg-chelatase, inserting a magnesium ion into Protoporphyrin IX to make Mg-protoporphyrin IX.
Reaction:
ATP + protoporphyrin IX + Mg2+ + H2O = ADP + phosphate + Mg-protoporphyrin IX + 2 H+.
Operon usage
Figure 2: This gene has been used in an operon with other genes responsible for the synthesis pathway from Protoporphyrin IX to MG-protoporphyrin IX. ChlI1 and ChlD form an Mg-chelatase complex, which acts upon protoporphyrin, catalysing the insertion of a Magnesium ion into the centre of the protoporphyrin IX. GUN4 aids this reaction by activating the Mg-chelatase enzyme complex.
The plasmid is under the control of the lac promoter.
The entire operon can be found at BBa_K1326008.
Future plans involve adding ChlH to this operon, which binds Mg-chelatase with GUN4 to protoporphyrin.
ChlI structure
Figure 3: ChlI protein crystal structure.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12INCOMPATIBLE WITH RFC[12]Illegal NheI site found at 523
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
Amino Acid Sequence
MPS
| None |