Comprehensive in silico prediction and analysis of chlamydial outer membrane proteins reflects evolution and life style of the Chlamydiae.
BACKGROUND
Chlamydiae are obligate intracellular bacteria comprising some of the most important bacterial pathogens of animals and humans. Although chlamydial outer membrane proteins play a key role for attachment to and entry into host cells, only few have been described so far. We developed a comprehensive, multiphasic in silico approach, including the calculation of clusters of orthologues, to predict outer membrane proteins using conservative criteria. We tested this approach using Escherichia coli (positive control) and Bacillus subtilis (negative control), and applied it to five chlamydial species; Chlamydia trachomatis, Chlamydia muridarum, Chlamydia (a.k.a. Chlamydophila) pneumoniae, Chlamydia (a.k.a. Chlamydophila) caviae, and Protochlamydia amoebophila.


RESULTS
In total, 312 chlamydial outer membrane proteins and lipoproteins in 88 orthologous clusters were identified, including 238 proteins not previously recognized to be located in the outer membrane. Analysis of their taxonomic distribution revealed an evolutionary conservation among Chlamydiae, Verrucomicrobia, Lentisphaerae and Planctomycetes as well as lifestyle-dependent conservation of the chlamydial outer membrane protein composition.


CONCLUSIONS
This analysis suggested a correlation between the outer membrane protein composition and the host range of chlamydiae and revealed a common set of outer membrane proteins shared by these intracellular bacteria. The collection of predicted chlamydial outer membrane proteins is available at the online database pCOMP http://www.microbial-ecology.net/pcomp and might provide future guidance in the quest for anti-chlamydial vaccines.
Heinz
Eva
E
Department of Microbial Ecology, Faculty of Life Sciences, University of Vienna, Vienna, Austria. heinz@microbial-ecology.net
Tischler
Patrick
P
Rattei
Thomas
T
Myers
Garry
G
Wagner
Michael
M
Horn
Matthias
M
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D002689:Chlamydia / Q000145:classification / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D023502:Chlamydia muridarum / Q000145:classification / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D002692:Chlamydia trachomatis / Q000145:classification / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D019295:Computational Biology / Q000379:methods*; D019143:Evolution, Molecular; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D012984:Software
D001425:Bacterial Outer Membrane Proteins; D008074:Lipoproteins