The compartmentalized bacteria of the planctomycetes-verrucomicrobia-chlamydiae superphylum have membrane coat-like proteins.
The development of the endomembrane system was a major step in eukaryotic evolution. Membrane coats, which exhibit a unique arrangement of beta-propeller and alpha-helical repeat domains, play key roles in shaping eukaryotic membranes. Such proteins are likely to have been present in the ancestral eukaryote but cannot be detected in prokaryotes using sequence-only searches. We have used a structure-based detection protocol to search all proteomes for proteins with this domain architecture. Apart from the eukaryotes, we identified this protein architecture only in the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC) bacterial superphylum, many members of which share a compartmentalized cell plan. We determined that one such protein is partly localized at the membranes of vesicles formed inside the cells in the planctomycete Gemmata obscuriglobus. Our results demonstrate similarities between bacterial and eukaryotic compartmentalization machinery, suggesting that the bacterial PVC superphylum contributed significantly to eukaryogenesis.
Santarella-Mellwig
Rachel
R
European Molecular Biology Laboratory, Heidelberg, Germany.
Franke
Josef
J
Jaedicke
Andreas
A
Gorjánácz
Mátyás
M
Bauer
Ulrike
U
Budd
Aidan
A
Mattaj
Iain W
IW
Devos
Damien P
DP
D001419:Bacteria / Q000145:classification / Q000166:cytology / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000502:physiology; D005075:Biological Evolution; D002451:Cell Compartmentation; D008565:Membrane Proteins / Q000737:chemistry* / Q000502:physiology; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D020543:Proteome; D020539:Sequence Analysis, Protein
D001426:Bacterial Proteins; D008565:Membrane Proteins; D020543:Proteome