Scientists sequence genome of the N2-fixing, soil-living bacterium Azotobacter ...( Blacksburg Va. A collaboration of r...)

Blacksburg, Va. A collaboration of researchers, which includes scientists at the Virginia Bioinformatics Institute (VBI) and Virginia Tech, have completed the genome sequence of Azotobacter vinelandii, uncovering important genetic information that will contribute to a more complete understanding of the biology of this versatile, soil-living bacterium. The work will help advance research on A. vinelandii's role as a model study organism for investigation of nitrogen fixation and other biochemical processes. It will also pave the way for new applications in biotechnology, including the possible use of A. vinelandii as a "factory" for the production of other proteins, in particular those that may be damaged by the presence of oxygen.

A. vinelandii lives in soil and has the ability to convert nitrogen from the atmosphere into ammonia via bacterial enzymes called nitrogenases. Nitrogen fixation is essential for life since different nitrogen-containing molecules are used to produce DNA and the amino acids that are the building blocks of proteins. For most bacteria, the nitrogenase enzymes involved in nitrogen fixation are very susceptible to destruction by oxygen. A. vinelandii is one of the few bacteria that can fix nitrogen in the presence of oxygen, using three distinct nitrogenase systems.

The work of the Azotobacter vinelandii genome project team, which will be featured on the cover of the second July 2009 issue (14) of the Journal of Bacteriology*, identifies unique features of the A. vinelandii genome that explain how the bacteria is involved in oxygen-sensitive reactions such as nitrogen fixation, while maintaining strictly aerobic metabolism.

A. vinelandii has one of the highest respiratory rates of any known bacterium and has the capacity to maintain low levels of cytoplasmic oxygen through a process called respiratory protection. The sequence of the bacteria's g
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