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Interplay Between an AAA Module and an Integrin I Domain May Regulate the Function of Magnesium Chelatase

Fodje, Michel LU ; Hansson, Andreas LU ; Olsen, J G; Gough, Simon LU ; Willows, R D; Al-Karadaghi, Salam LU and Hansson, Mats LU (2001) In Journal of Molecular Biology 311(1). p.111-122
Abstract
In chlorophyll biosynthesis, insertion of Mg2+ 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 % (Rfree = 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.... (More)
In chlorophyll biosynthesis, insertion of Mg2+ 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 % (Rfree = 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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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
AAA module, integrin I domain, magnesium chelatase, chlorophyll synthesis, porphyrin metallation
in
Journal of Molecular Biology
volume
311
issue
1
pages
111 - 122
publisher
Elsevier
external identifiers
  • scopus:0035800571
ISSN
1089-8638
DOI
10.1006/jmbi.2001.4834
language
English
LU publication?
yes
id
80923b65-53c8-4ef2-a2c0-1205bc64e821 (old id 124958)
date added to LUP
2007-07-05 09:17:49
date last changed
2018-10-03 11:25:11
@article{80923b65-53c8-4ef2-a2c0-1205bc64e821,
  abstract     = {In chlorophyll biosynthesis, insertion of Mg2+ 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 % (Rfree = 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.},
  author       = {Fodje, Michel and Hansson, Andreas and Olsen, J G and Gough, Simon and Willows, R D and Al-Karadaghi, Salam and Hansson, Mats},
  issn         = {1089-8638},
  keyword      = {AAA module,integrin I domain,magnesium chelatase,chlorophyll synthesis,porphyrin metallation},
  language     = {eng},
  number       = {1},
  pages        = {111--122},
  publisher    = {Elsevier},
  series       = {Journal of Molecular Biology},
  title        = {Interplay Between an AAA Module and an Integrin I Domain May Regulate the Function of Magnesium Chelatase},
  url          = {http://dx.doi.org/10.1006/jmbi.2001.4834},
  volume       = {311},
  year         = {2001},
}