Type II secretion: from structure to function | FEMS Microbiology Letters | Oxford Academic
The bacterial flagellar filament, largely composed of a single protein, flagellin a homolog of the N-terminal domain of bacterial type IV pilin, showing once . The two views are related by a rotation of 80° about the vertical axis. () Detailed structural and assembly model of the type II secretion pilus from sparse data. Microbiology. Nov;(Pt 11) Type II protein secretion and its relationship to bacterial type IV pili and archaeal flagella. Peabody CR(1), Chung . Type II protein secretion and its relationship to bacterial type IV pili and archaeal flagella. Microbiology , – Pearson, J.P., Passador, L., Iglewski.
Archaella are functionally analogous yet structurally and genetically unrelated to bacterial flagella Jarrell and Albers, ; Shahapure et al.Old & Odd: Archaea, Bacteria & Protists - CrashCourse Biology #35
T4P have been studied to a greater extent in bacteria, in part because they are often virulence factors Giltner et al. However, recent investigations have revealed a repertoire of archaeal T4P—highlighting implications for regulatory complexity and functional diversity.
Deletion of pilB1 led to a lack of pili as observed through electron microscopy and a defect in adhesion.
The molecular composition of PilB1-dependent pili has not yet been determined, however Losensky and coauthors noted that there are over 30 candidate pilins in the Hbt. Experimentally studied type IV pili in archaeal species: Some of these pilins could be associated with additional functions. There could be more archaeal T4P-related surface structures that scavenge macromolecules as well, like the bindosome of Sulfolobus solfataricus Zolghadr et al.
Investigations of archaeal T4P leave open the possibility for undiscovered mechanisms for contacting abiotic surfaces or other cells. Similar residual adhesion has been observed in Hfx.
Summary: Type II secretion system (T2SS), protein L
There are two other cell-to-cell contact phenomena in Hfx. Additional types of extracellular polymers or fibers found in bacterial species could be present in archaea, such as amyloid protein Chimileski et al.
Unusual, genetically ambiguous non-T4P structures have already been observed in other archaeal species, including the hamus of the SM1 euryarchaeon Moissl et al. GspL is predicted to contain a large cytoplasmic domain and has been shown to interact with the autophosphorylating cytoplasmic membrane protein GspE.
Pfam: Family: T2SSL (PF)
This N-terminal domain is found in general secretion pathway protein L sequences from several Gram-negative bacteria. It is a cytoplasmic domain that shows structural homology with the superfamily of actin-like ATPases. Domain organisation Below is a listing of the unique domain organisations or architectures in which this domain is found.
The graphic that is shown by default represents the longest sequence with a given architecture. Each row contains the following information: Gla, EGF x 2, Trypsin.
Type II protein secretion and its relationship to bacterial type IV pili and archaeal flagella.
This example describes an architecture with one Gla domain, followed by two consecutive EGF domains, and finally a single Trypsin domain a link to the page in the Pfam site showing information about the sequence that the graphic describes the UniProt description of the protein sequence the number of residues in the sequence the Pfam graphic itself. Note that you can see the family page for a particular domain by clicking on the graphic.
You can also choose to see all sequences which have a given architecture by clicking on the Show link in each row. Finally, because some families can be found in a very large number of architectures, we load only the first fifty architectures by default.