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Bacterial Terminal Oxidases. Studies in Bacillus subtilis

Winstedt, Lena LU (2002)
Abstract (Swedish)
Popular Abstract in Swedish

Alla organismer som använder syre har i sina celler en s. k. elektrontransportkedja för att generera energi. Kedjan består av enzymer som sitter i mitokondriens inre membran eller i bakteriens membran. Enzymerna genomgår oxidation och reduktion när elektronerna passerar genom kedjan. Då genereras energi som kan användas för olika processer, t. ex. transport av ämnen in i och ut ur cellen. I det sista steget i kedjan omvandlas syre till vatten. Denna reaktion katalyseras av enzymer som kallas terminala oxidaser. I mitokondrier (i t. ex. människa) finns endast en typ av terminala oxidaser medan bakterier i regel har två eller flera. Bakterien Bacillus subtilis har tre eller fyra terminala oxidaser.... (More)
Popular Abstract in Swedish

Alla organismer som använder syre har i sina celler en s. k. elektrontransportkedja för att generera energi. Kedjan består av enzymer som sitter i mitokondriens inre membran eller i bakteriens membran. Enzymerna genomgår oxidation och reduktion när elektronerna passerar genom kedjan. Då genereras energi som kan användas för olika processer, t. ex. transport av ämnen in i och ut ur cellen. I det sista steget i kedjan omvandlas syre till vatten. Denna reaktion katalyseras av enzymer som kallas terminala oxidaser. I mitokondrier (i t. ex. människa) finns endast en typ av terminala oxidaser medan bakterier i regel har två eller flera. Bakterien Bacillus subtilis har tre eller fyra terminala oxidaser. Ett av dessa är cytokrom bd, en typ av oxidas som bara hittats i bakterier och arkeabakterier. Här har jag använt B. subtilis för att studera terminala oxidaser i bakterier. Fokus har varit på cytokrom bd men jag har även studerat hur och när de olika terminala oxidaserna används i B. subtilis. Vidare har cytokrom bd studerats i en närbesläktad bakterie, Enterococcus faecalis, som är vanlig vid sjukhusförvärvade infektioner. I E. faecalis är cytokrom bd intressant ur medicinsk synvinkel eftersom det har visat sig ha betydelse för virulensen hos vissa bakterier. B. subtilis har ett terminalt oxidas som liknar det i mitokondrien. Denna typ är ganska välstuderat men man vet ganska lite om hur enzymet sätts ihop. Enzymet innehåller koppar men det är inte känt hur kopparatomerna sätts in. Vi har därför studerat ihopsättning av detta terminala oxidas med fokus på kopparinsättning. (Less)
Abstract
The final step in aerobic respiratory pathways is catalyzed by terminal oxidases. Bacteria generally have two or more terminal oxidases. Aerobically grown Bacillus subtilis synthesize three terminal oxidases: one cytochrome c oxidase, cytochrome caa3 and two quinol oxidases, cytochrome aa3 and cytochrome bd. In addition, a fourth cytochrome of bd-type has been predicted from the genome sequence. Cytochrome caa3 and cytochrome aa3 both belong to the well characterized family of heme-copper oxidases. Cytochrome bd is unrelated to the heme-copper oxidases and has been less studied. To characterize cytochrome bd in gram-positive bacteria, we cloned four genes, cydABCD, required for the expression of a functional enzyme. The cyd genes were... (More)
The final step in aerobic respiratory pathways is catalyzed by terminal oxidases. Bacteria generally have two or more terminal oxidases. Aerobically grown Bacillus subtilis synthesize three terminal oxidases: one cytochrome c oxidase, cytochrome caa3 and two quinol oxidases, cytochrome aa3 and cytochrome bd. In addition, a fourth cytochrome of bd-type has been predicted from the genome sequence. Cytochrome caa3 and cytochrome aa3 both belong to the well characterized family of heme-copper oxidases. Cytochrome bd is unrelated to the heme-copper oxidases and has been less studied. To characterize cytochrome bd in gram-positive bacteria, we cloned four genes, cydABCD, required for the expression of a functional enzyme. The cyd genes were expressed maximally in late exponential growth phase under conditions of low oxygen tension. The roles of different terminal oxidases in B. subtilis were investigated. We found that no single terminal oxidase is essential but one of the quinol oxidases cytochrome aa3 or cytochrome bd is required for aerobic growth. A cydABCD gene cluster, similar to that in B. subtilis, was identified in the closely related bacterium Enterococcus faecalis. The genes encode a cytochrome bd which can function as a terminal oxidase. Although the heme-copper oxidases have been intensely studied, there is not much known about the assembly of this type of enzymes. We have studied two genes, ctaG and ypmQ, required for the synthesis of a functional cytochrome caa3. Our results indicate that the genes are involved in assembly of the di-copper (CuA) center. (Less)
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author
opponent
  • Prof Glaser, Philippe, Laboratoire de Génomique des Microorganismes Pathogènes, Institut Pasteur, France.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
mycology, virology, mykologi, bakteriologi, Mikrobiologi, bacteriology, Microbiology, di-copper center, cytochrome oxidase, Enterococcus faecalis, cytochrome bd, Bacillus subtilis, terminal oxidase, virologi
pages
108 pages
publisher
Lena Winstedt, Department of cell and organism biology, Sölvegatan 12, S-223 62 Lund, Sweden,
defense location
Biology lecture hall, Sölvegatan 35, Lund
defense date
2002-06-14 10:00
ISBN
91-628-5303-1
language
English
LU publication?
yes
id
2d3836f7-9d51-4ba1-b5e3-e91dd498842a (old id 464720)
date added to LUP
2007-09-07 11:43:38
date last changed
2016-09-19 08:45:11
@misc{2d3836f7-9d51-4ba1-b5e3-e91dd498842a,
  abstract     = {The final step in aerobic respiratory pathways is catalyzed by terminal oxidases. Bacteria generally have two or more terminal oxidases. Aerobically grown Bacillus subtilis synthesize three terminal oxidases: one cytochrome c oxidase, cytochrome caa3 and two quinol oxidases, cytochrome aa3 and cytochrome bd. In addition, a fourth cytochrome of bd-type has been predicted from the genome sequence. Cytochrome caa3 and cytochrome aa3 both belong to the well characterized family of heme-copper oxidases. Cytochrome bd is unrelated to the heme-copper oxidases and has been less studied. To characterize cytochrome bd in gram-positive bacteria, we cloned four genes, cydABCD, required for the expression of a functional enzyme. The cyd genes were expressed maximally in late exponential growth phase under conditions of low oxygen tension. The roles of different terminal oxidases in B. subtilis were investigated. We found that no single terminal oxidase is essential but one of the quinol oxidases cytochrome aa3 or cytochrome bd is required for aerobic growth. A cydABCD gene cluster, similar to that in B. subtilis, was identified in the closely related bacterium Enterococcus faecalis. The genes encode a cytochrome bd which can function as a terminal oxidase. Although the heme-copper oxidases have been intensely studied, there is not much known about the assembly of this type of enzymes. We have studied two genes, ctaG and ypmQ, required for the synthesis of a functional cytochrome caa3. Our results indicate that the genes are involved in assembly of the di-copper (CuA) center.},
  author       = {Winstedt, Lena},
  isbn         = {91-628-5303-1},
  keyword      = {mycology,virology,mykologi,bakteriologi,Mikrobiologi,bacteriology,Microbiology,di-copper center,cytochrome oxidase,Enterococcus faecalis,cytochrome bd,Bacillus subtilis,terminal oxidase,virologi},
  language     = {eng},
  pages        = {108},
  publisher    = {ARRAY(0x83ac330)},
  title        = {Bacterial Terminal Oxidases. Studies in Bacillus subtilis},
  year         = {2002},
}