A bioinformatic strategy for the detection, classification and analysis of bacterial autotransporters.
Autotransporters are secreted proteins that are assembled into the outer membrane of bacterial cells. The passenger domains of autotransporters are crucial for bacterial pathogenesis, with some remaining attached to the bacterial surface while others are released by proteolysis. An enigma remains as to whether autotransporters should be considered a class of secretion system, or simply a class of substrate with peculiar requirements for their secretion. We sought to establish a sensitive search protocol that could identify and characterize diverse autotransporters from bacterial genome sequence data. The new sequence analysis pipeline identified more than 1500 autotransporter sequences from diverse bacteria, including numerous species of Chlamydiales and Fusobacteria as well as all classes of Proteobacteria. Interrogation of the proteins revealed that there are numerous classes of passenger domains beyond the known proteases, adhesins and esterases. In addition the barrel-domain-a characteristic feature of autotransporters-was found to be composed from seven conserved sequence segments that can be arranged in multiple ways in the tertiary structure of the assembled autotransporter. One of these conserved motifs overlays the targeting information required for autotransporters to reach the outer membrane. Another conserved and diagnostic motif maps to the linker region between the passenger domain and barrel-domain, indicating it as an important feature in the assembly of autotransporters.
Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.
Nermin
N
Celik
Chaille T
CT
Webb
Denisse L
DL
Leyton
Kathryn E
KE
Holt
Eva
E
Heinz
Rebecca
R
Gorrell
Terry
T
Kwok
Thomas
T
Naderer
Richard A
RA
Strugnell
Terence P
TP
Speed
Rohan D
RD
Teasdale
Vladimir A
VA
Likić
Trevor
T
Lithgow
D018829:Adhesins, Bacterial / Q000378:metabolism; D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000737:chemistry; D001692:Biological Transport; D002695:Chlamydiales / Q000378:metabolism; D019295:Computational Biology / Q000379:methods*; D004926:Escherichia coli / Q000378:metabolism; D045182:Fusobacteria / Q000378:metabolism; D006801:Humans; D008390:Markov Chains; D010802:Phylogeny; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D043367:Ralstonia / Q000378:metabolism; D012984:Software
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins