Advanced

Study on the role of YozB (CtaM) in Bacillus subtilis

Nuorbaksh, Shaian (2017) MOBM01 20171
Degree Projects in Molecular Biology
Popular Abstract
A mysterious gene found in many bacteria

Recently, a gene called ctaM was discovered in Staphylococcus aureus, a common cause of skin infections etc., required for the bacterium to respire efficiently. It was demonstrated that the protein encoded by this gene is essential for the function of cytochrome aa3, that catalyzes the reduction of O2 to form H2O in respiration. A gene encoding a similar protein has also been found in Bacillus anthracis, the causative agent of anthrax. This protein is crucial for the full respiratory activity. In this master degree project, I have studied the CtaM homolog YozB in the well characterized experimental model bacterium Bacillus subtilis .

Based on results with constructed mutants, genetic... (More)
A mysterious gene found in many bacteria

Recently, a gene called ctaM was discovered in Staphylococcus aureus, a common cause of skin infections etc., required for the bacterium to respire efficiently. It was demonstrated that the protein encoded by this gene is essential for the function of cytochrome aa3, that catalyzes the reduction of O2 to form H2O in respiration. A gene encoding a similar protein has also been found in Bacillus anthracis, the causative agent of anthrax. This protein is crucial for the full respiratory activity. In this master degree project, I have studied the CtaM homolog YozB in the well characterized experimental model bacterium Bacillus subtilis .

Based on results with constructed mutants, genetic crossings, bacterial growth, and biochemical tests, I have found that YozB is important for respiration also in B. subtilis and that lack of this protein specifically affects cytochrome a respiratory enzymes. These enzymes uniquely contain a variant of heme called heme A and belong to the so called heme-copper family of respiratory oxidases. I demonstrate that the two heme-copper oxidases are assembled in the membrane and incorporate heme A also when YozB is missing. However, in the absence of YozB, one oxidase (cytochrome aa3) seems inactive and the other (cytochrome caa3) is defective. Two oxidases, cytochromes bd and aa3, are important for the growth of Bacillus subtilis. The bacterium cannot grow if the genes for both these oxidases are simultaneously inactivated, at least not under oxic conditions. I found that it was not possible to delete genes for cytochrome bd in a mutant of Bacillus subtilis deficient in YozB. This suggests that cytochrome aa3 activity requires YozB. In conclusion, YozB is crucial for function of heme-copper oxidases in bacteria. Interestingly, the yozB gene and similar genes are only found in species that use heme A. The gene is not found, for instance, in the organisms that use fermentation for growth or in anaerobic bacteria. The exact function of CtaM/YozB in assembly of heme-copper oxidases remain to be determined.

Master’s Degree Project in Biology/Molecular Biology/Microbiology 30 credits 2017
Department of Biology, Lund University
Advisor: Prof. Lars Hederstedt and Prof. Claes von Wachenfeldt (Less)
Please use this url to cite or link to this publication:
author
Nuorbaksh, Shaian
supervisor
organization
course
MOBM01 20171
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8925410
date added to LUP
2017-09-12 09:50:56
date last changed
2017-09-12 09:50:56
@misc{8925410,
  author       = {Nuorbaksh, Shaian},
  language     = {eng},
  note         = {Student Paper},
  title        = {Study on the role of YozB (CtaM) in Bacillus subtilis},
  year         = {2017},
}