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Low spin heme A in the heme A biosynthetic protein CtaA from Bacillus subtilis

Svensson, Birgitta; Anderson, Kristoffer K. and Hederstedt, Lars LU (1996) In European Journal of Biochemistry p.287-295
Abstract
Synthesis of heme A from heme B (protoheme IX) most likely occurs in two steps with heme O as an intermediate. Bacillus subtilis CtaB, an integral membrane protein, functions in farnesylation of heme B to form heme O. CtaA, also a membrane protein, is required for heme A synthesis from heme O and appears to be a monooxygenase and/or a dehydrogenase. Wild-type ctaA and ctaB expressed together from plasmids in B. subtilis resulted in CtaA containing equimolar amounts of low-spin heme B and heme A; this form of CtaA was named cyt ba -CTA. A mutant ctaB gene was identified and characterised. It encodes a truncated CtaB polypeptide. Wild-type ctaA and the mutant ctaB gene on plasmids resulted in CtaA containing mainly low-spin heme B; this... (More)
Synthesis of heme A from heme B (protoheme IX) most likely occurs in two steps with heme O as an intermediate. Bacillus subtilis CtaB, an integral membrane protein, functions in farnesylation of heme B to form heme O. CtaA, also a membrane protein, is required for heme A synthesis from heme O and appears to be a monooxygenase and/or a dehydrogenase. Wild-type ctaA and ctaB expressed together from plasmids in B. subtilis resulted in CtaA containing equimolar amounts of low-spin heme B and heme A; this form of CtaA was named cyt ba -CTA. A mutant ctaB gene was identified and characterised. It encodes a truncated CtaB polypeptide. Wild-type ctaA and the mutant ctaB gene on plasmids resulted in CtaA containing mainly low-spin heme B; this variant was named cyt b -CTA. The heme B component in cyt ba -CTA and cyt b -CTA showed identical properties; a mid-point redox potential of +85 mV, an EPR gmax signal at 3.7, and a split α-band light absorption peak. The heme A component in cyt ba -CTA showed a mid-point potential of +242 mV, an EPR gmax signal at 3.5, and the α-band light absorption peak at 585 nm. It is suggested that the CtaA protein contains two heme binding sites, one for heme B and one for substrate heme. The heme B would play a role in electron transfer, i.e. function as a cytochrome, in the monooxygenase and/or dehydrogenase reaction catalysed by CtaA whereas heme O/heme A would be substrate/product.
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published
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in
European Journal of Biochemistry
pages
287 - 295
publisher
Wiley-Blackwell
ISSN
0014-2956
DOI
10.1111/j.1432-1033.1996.0287q.x
language
English
LU publication?
yes
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4e283da8-ec53-42f3-81c2-a77776c7909f
date added to LUP
2017-07-18 10:05:19
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2017-08-14 12:31:36
@article{4e283da8-ec53-42f3-81c2-a77776c7909f,
  abstract     = {Synthesis of heme A from heme B (protoheme IX) most likely occurs in two steps with heme O as an intermediate. Bacillus subtilis CtaB, an integral membrane protein, functions in farnesylation of heme B to form heme O. CtaA, also a membrane protein, is required for heme A synthesis from heme O and appears to be a monooxygenase and/or a dehydrogenase. Wild-type ctaA and ctaB expressed together from plasmids in B. subtilis resulted in CtaA containing equimolar amounts of low-spin heme B and heme A; this form of CtaA was named cyt ba -CTA. A mutant ctaB gene was identified and characterised. It encodes a truncated CtaB polypeptide. Wild-type ctaA and the mutant ctaB gene on plasmids resulted in CtaA containing mainly low-spin heme B; this variant was named cyt b -CTA. The heme B component in cyt ba -CTA and cyt b -CTA showed identical properties; a mid-point redox potential of +85 mV, an EPR gmax signal at 3.7, and a split α-band light absorption peak. The heme A component in cyt ba -CTA showed a mid-point potential of +242 mV, an EPR gmax signal at 3.5, and the α-band light absorption peak at 585 nm. It is suggested that the CtaA protein contains two heme binding sites, one for heme B and one for substrate heme. The heme B would play a role in electron transfer, i.e. function as a cytochrome, in the monooxygenase and/or dehydrogenase reaction catalysed by CtaA whereas heme O/heme A would be substrate/product.<br/>},
  author       = {Svensson, Birgitta and Anderson, Kristoffer K. and Hederstedt, Lars},
  issn         = {0014-2956},
  language     = {eng},
  pages        = {287--295},
  publisher    = {Wiley-Blackwell},
  series       = {European Journal of Biochemistry},
  title        = {Low spin heme A in the heme A biosynthetic protein CtaA from <em>Bacillus subtilis</em>},
  url          = {http://dx.doi.org/10.1111/j.1432-1033.1996.0287q.x},
  year         = {1996},
}