Chapter 5 Magnesium Chelatase

Part of the Advances in Photosynthesis and Respiration book series (AIPH, volume 31)

Summary

In chlorophyll biosynthesis, Mg2+ is inserted into protoporphyrin IX in an ATP-dependent process catalyzed by three soluble proteins. The three proteins involved in the magnesium insertion have average molecular weights of 40, 70 and 140 kDa. In bacteriochlorophyll synthesizing organisms they are designated as BchI, BchD and BchH and in chlorophyll synthesizing organisms they are referred to as ChI, ChD and ChH. The 40 kDa subunit is compared with the Golgi membrane protein NSF-D2, Heat shock locus protein HslU and the δ′ subunit of the DNA polymerase III (PolIII-δ′). The 70 kDa subunit and its complex formation with the 40 kDa subunit are also described; along with the 140 kDa subunit, which is referred to as the H subunit and in barley, corresponds to the Xantha – F gene product. The Gun4 protein, a porphyrin binding stimulator protein of the magnesium chelatase is also discussed.

Keywords

Mutant Subunit Hexameric Ring Heat Shock Locus Magnesium Chelatase Thumb Domain 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Abbreviations

Chl

chlorophyll;

Proto

protochlorophyll;

Bchl

bacteriochlorophyll;

BchI, BchD, BchH

subunits of Mg-Proto chelatase in Bchl synthesizing organisms;

ChI, ChD, ChH

subunits of Mg-Proto chelatase in Chl synthesizing orga­nisms;

MAD

multiple wavelength anomalous dispersion;

Hs1U

chaperone part of the bacterial homologue of the mammalian proteasome;

PolIII-δ′

delta subunit of the clamp-loader complex of E. coli DNA polymerase III;

NSF-D2

N-ethylmaleimide-sensitive fusion protein D2;

M1-L-M2

linker domain that contains 36% praline and 26% aspartate + glutamate residues;

ITA2

human collagen receptor;

ITAX

human leucocyte adhesion receptor;

ITAE

integrin α-E precursor of mouse;

CAMA

cartilage matrix protein of chicken;

MIDAS

metal ion dependent adhesion site;

N-dom

N-terminal domain;

C-dom

C-terminal domain;

Gun

4 protein a porphyrin binding stimulator protein of the magnesium chelatase

Notes

Acknowledgment

This content of this chapter was researched during a stay of C.G. K. at the Institute of Phytopathology and Applied Zoology, IFZ, of the Justus Liebig University, Giessen. D.v.W. acknowledges the support of a Mercator Professorship from the Deutsche Forschungsgemeinschaft. We thank Professor Karl-Heinz Kogel IFZ, Justus Liebig University Giessen for his generous support.

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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Department of Crop and Soil SciencesWashington State UniversityPullmanUSA
  2. 2.Department of Crop and Soil Sciences and School of Molecular Biosciences,Washington State University, Pullman, WA99164, USA andInstitute of Phytopathology and Applied ZoologyIFZ,Germany

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