ATPases and phosphate exchange activities in magnesium chelatase subunits of Rhodobacter sphaeroides
(1997) In Proceedings of the National Academy of Sciences 94(24). p.13351-13356- Abstract
- Three separate proteins, BchD, BchH, and BchI, together with ATP, insert magnesium into protoporphyrin IX. An analysis of ATP utilization by the subunits revealed the following: BchH catalyzed ATP hydrolysis at the rate of 0.9 nmol per min per mg of protein. BchI and BchD, tested individually, had no ATPase activity but, when combined, hydrolyzed ATP at the rate of 117.9 nmol/min per mg of protein. Magnesium ions were required for the ATPase activities of both BchH and BchI+D, and these activities were inhibited 50% by 2 mM o-phenanthroline. BchI additionally catalyzed a phosphate exchange reaction from ATP and ADP. We conclude that ATP hydrolysis by BchI+D is required for an activation step in the magnesium chelatase reaction, whereas... (More)
- Three separate proteins, BchD, BchH, and BchI, together with ATP, insert magnesium into protoporphyrin IX. An analysis of ATP utilization by the subunits revealed the following: BchH catalyzed ATP hydrolysis at the rate of 0.9 nmol per min per mg of protein. BchI and BchD, tested individually, had no ATPase activity but, when combined, hydrolyzed ATP at the rate of 117.9 nmol/min per mg of protein. Magnesium ions were required for the ATPase activities of both BchH and BchI+D, and these activities were inhibited 50% by 2 mM o-phenanthroline. BchI additionally catalyzed a phosphate exchange reaction from ATP and ADP. We conclude that ATP hydrolysis by BchI+D is required for an activation step in the magnesium chelatase reaction, whereas ATPase activity of BchH and the phosphate exchange activity of BchI participate in subsequent reactions leading to the insertion of Mg2+ into protoporphyrin IX. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/8001545
- author
- Hansson, Mats LU and Kannangara, C. G.
- publishing date
- 1997
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Adenosine Diphosphate/metabolism, Adenosine Triphosphatases/antagonists & inhibitors/*metabolism, Enzyme Activation, Enzyme Inhibitors/pharmacology, Lyases/antagonists & inhibitors/chemistry/*metabolism, Phenanthrolines/pharmacology, Phosphates/*metabolism, Protoporphyrins/chemistry, Rhodobacter sphaeroides/*enzymology, Sodium Fluoride/pharmacology
- in
- Proceedings of the National Academy of Sciences
- volume
- 94
- issue
- 24
- pages
- 13351 - 13356
- publisher
- National Academy of Sciences
- external identifiers
-
- scopus:0030695453
- ISSN
- 1091-6490
- DOI
- 10.1073/pnas.94.24.13351
- language
- English
- LU publication?
- no
- additional info
- 24
- id
- 5527c29f-0d83-402d-af0d-ffb3085be4a0 (old id 8001545)
- alternative location
- http://www.ncbi.nlm.nih.gov/pubmed/9371849
- date added to LUP
- 2016-04-01 12:29:35
- date last changed
- 2022-01-27 05:48:45
@article{5527c29f-0d83-402d-af0d-ffb3085be4a0, abstract = {{Three separate proteins, BchD, BchH, and BchI, together with ATP, insert magnesium into protoporphyrin IX. An analysis of ATP utilization by the subunits revealed the following: BchH catalyzed ATP hydrolysis at the rate of 0.9 nmol per min per mg of protein. BchI and BchD, tested individually, had no ATPase activity but, when combined, hydrolyzed ATP at the rate of 117.9 nmol/min per mg of protein. Magnesium ions were required for the ATPase activities of both BchH and BchI+D, and these activities were inhibited 50% by 2 mM o-phenanthroline. BchI additionally catalyzed a phosphate exchange reaction from ATP and ADP. We conclude that ATP hydrolysis by BchI+D is required for an activation step in the magnesium chelatase reaction, whereas ATPase activity of BchH and the phosphate exchange activity of BchI participate in subsequent reactions leading to the insertion of Mg2+ into protoporphyrin IX.}}, author = {{Hansson, Mats and Kannangara, C. G.}}, issn = {{1091-6490}}, keywords = {{Adenosine Diphosphate/metabolism; Adenosine Triphosphatases/antagonists & inhibitors/*metabolism; Enzyme Activation; Enzyme Inhibitors/pharmacology; Lyases/antagonists & inhibitors/chemistry/*metabolism; Phenanthrolines/pharmacology; Phosphates/*metabolism; Protoporphyrins/chemistry; Rhodobacter sphaeroides/*enzymology; Sodium Fluoride/pharmacology}}, language = {{eng}}, number = {{24}}, pages = {{13351--13356}}, publisher = {{National Academy of Sciences}}, series = {{Proceedings of the National Academy of Sciences}}, title = {{ATPases and phosphate exchange activities in magnesium chelatase subunits of Rhodobacter sphaeroides}}, url = {{http://dx.doi.org/10.1073/pnas.94.24.13351}}, doi = {{10.1073/pnas.94.24.13351}}, volume = {{94}}, year = {{1997}}, }