Stackebrandt, E. et al., 1988 
The Proteobacteria are a major group (phylum) of bacteria. They include a wide variety of pathogens, such as Escherichia, Salmonella, Vibrio, Helicobacter, and many other notable genera. Others are free-living (non-parasitic), and include many of the bacteria responsible for nitrogen fixation.
Carl Woese established this grouping in 1987, calling it informally the "purple bacteria and their relatives". Because of the great diversity of forms found in this group, the Proteobacteria are named after Proteus, a Greek god of the sea capable of assuming many different shapes; it is not named after the genus Proteus.
All proteobacteria are Gram-negative, with an outer membrane mainly composed of lipopolysaccharides. Many move about using flagella, but some are nonmotile or rely on bacterial gliding. The last include the myxobacteria, a unique group of bacteria that can aggregate to form multicellular fruiting bodies. There is also a wide variety in the types of metabolism. Most members are facultatively or obligately anaerobic, chemoautotrophs, and heterotrophic, but there are numerous exceptions. A variety of genera, which are not closely related to each other, convert energy from light through photosynthesis. These are called purple bacteria, referring to their mostly reddish pigmentation.
|Phylogeny of Proteobacteria|
|Phylogeny of proteobacteria according to ARB living tree, iTOL, Bergey's and others.|
The group is defined primarily in terms of ribosomal RNA (rRNA) sequences. The Proteobacteria are divided into six sections, referred to by the Greek letters alpha through zeta. These were previously regarded as subclasses of the phylum, but they are now treated as classes. The naming convention for the classes is to style each in italics with a capital first letter: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Epsilonproteobacteria, and Acidithiobacillia. Class "Zetaproteobacteria" is not yet validly published.
The alpha, beta, delta, and epsilon classes are monophyletic. The genus Acidithiobacillus, part of the Gammaproteobacteria until it was transferred to Class Acidithiobacillia in 2013, is paraphyletic to Betaproteobacteria according to multigenome alignment studies.
- Stackebrandt, E., et al. (1988). Proteobacteria classis nov., a name for the phylogenetic taxon that includes the "purple bacteria and their relatives". Int. J. Syst. Bacteriol. 38, 321–25.
- Madigan, M. and J. Martinko. (eds.) (2005). Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0-13-144329-1.
- Woese, C. R. (1987). "Bacterial evolution". Microbiological reviews 51 (2): 221–271. PMC 373105. PMID 2439888.
- "Proteobacteria". Discover Life: Tree of Life. Retrieved 2007-02-09.
- Lee, K. B., et al. (2005). The hierarchical system of the Alphaproteobacteria: description of Hyphomonadaceae fam. nov., Xanthobacteraceae fam. nov. and Erythrobacteraceae fam. nov. International Journal of Systematic and Evolutionary Microbiology 55(5), 1907-19.
- Krieg, N. R., et al. (2005). Bergey's Manual of Systematic Bacteriology: The Proteobacteria. Springer. ISBN 978-0-387-95040-2.
- Ciccarelli, F. D., et al. (2006). Toward automatic reconstruction of a highly resolved tree of life. Science 311(5765), 1283-87.
- Yarza, P., et al. (2010). Update of the All-Species Living Tree Project based on 16S and 23S rRNA sequence analyses. Systematic and Applied Microbiology 33(6), 291-99.
- Williams, K. P. and D. P. Kelly. (2013). Proposal for a new class within the Proteobacteria, the Acidithiobacillia, with the Acidithiobacillales as the type order. International Journal of Systematic and Evolutionary Microbiology. Published online ahead of print, January 18, 2013.
- Williams, K. P., et al. (2010). Phylogeny of Gammaproteobacteria. Journal of Bacteriology 192(9), 2305-14.
|Wikispecies has information related to: Proteobacteria|
- Proteobacteria information from Palaeos.
- Proteobacteria. – J. P. Euzéby: List of Prokaryotic names with Standing in Nomenclature.