PMC

Electron micrographs of whole sectioned G. obscuriglobus cells representative of the morphologies observed. Lower right: schematic of the electron micrographs with the paryphoplasm colored in grey. CM, cytoplasmic membrane (+cell wall); ICM, intracytoplasmic membrane; P, paryphoplasm; I, invaginations of the ICM; D, DNA; V, vesicle. Scale bar: 500 nm.

(A, B, and C) Electron micrographs of gp4978-immuno-labelled intra-paryphoplasmic vesicle-bearing G. obscuriglobus cells. Gold particles associated to membranes are indicated by arrows. Scale bars: 500 nm. (D) Chart of the distribution of 494 gold particles in the Cytoplasm (C), Paryphoplasm (P), Vesicle Membranes (VM), Cytoplasmic membrane (CM), and Intracytoplasmic membrane (ICM).

Global phylogeny of 212 organisms for which an alignment of 31 universal protein families could be built, adapted from , drawn with iTOL . Eukaryotes, archaea, and eubacteria are grouped with orange, green, and blue backgrounds, respectively. The number of MC proteins found in each proteome is indicated on the external arc with red bars (see Supporting Information for the complete proteome dataset). Note that this tree includes only two members of the PVC superphylum (both are planctomycetes).

Purified N-terminal 10-His tagged gp4978 was trypsin digested and the reaction was stopped at various time points. The resulting fragments were electrophoretically separated. (A) Coomassie-stained SDS-page gel; (B) Anti-His antibodies stained Western blot; (C) Molecular weight of the resulting fragments (the full-length protein has a predicted weight of 128 kDa and a calculated one of 124 kDa); (D) Positions of cleavage are reported on the predicted secondary structure (). The size of the arrow is relative to the susceptibility of the positions to cleavage.

Representative yeast and PVC MCs are illustrated. Left: predicted secondary structure. The amino-acid scale is represented at the top. The black horizontal line represents the sequence of each MC protein. The predicted secondary structure , α-helices (magenta) and β -strands (cyan) are indicated by colored bars above each line. The height of the bars is proportional to the confidence of the predictions. When an atomic structure is available, the corresponding fragment is highlighted by a grey box below the sequence. Sequences are aligned around the transition from mainly β-sheet to mainly α-helical. Right: predicted and observed tertiary structure: Predicted fold types are represented by coloured shapes, cyan hexagon for β-propeller and magenta oval for SPAH domain. Where known, the atomic structure is represented with the same coloring scheme. PDB codes of the represented structures are 3hxr and 3f7f , Nup120; 1xks and 3i4r , Nup133; 3i5p , Nup170; 1bpo and 1b89 , clathrin; and 2pm6 and 2pm9 , Sec31. Chc, clathrin heavy chain.