@article {19723,
	title = {Archaeosortases and exosortases are widely distributed systems linking membrane transit with posttranslational modification.},
	journal = {J Bacteriol},
	volume = {194},
	year = {2012},
	month = {2012 Jan},
	pages = {36-48},
	abstract = {<p>Multiple new prokaryotic C-terminal protein-sorting signals were found that reprise the tripartite architecture shared by LPXTG and PEP-CTERM: motif, TM helix, basic cluster. Defining hidden Markov models were constructed for all. PGF-CTERM occurs in 29 archaeal species, some of which have more than 50 proteins that share the domain. PGF-CTERM proteins include the major cell surface protein in Halobacterium, a glycoprotein with a partially characterized diphytanylglyceryl phosphate linkage near its C terminus. Comparative genomics identifies a distant exosortase homolog, designated archaeosortase A (ArtA), as the likely protein-processing enzyme for PGF-CTERM. Proteomics suggests that the PGF-CTERM region is removed. Additional systems include VPXXXP-CTERM/archeaosortase B in two of the same archaea and PEF-CTERM/archaeosortase C in four others. Bacterial exosortases often fall into subfamilies that partner with very different cohorts of extracellular polymeric substance biosynthesis proteins; several species have multiple systems. Variant systems include the VPDSG-CTERM/exosortase C system unique to certain members of the phylum Verrucomicrobia, VPLPA-CTERM/exosortase D in several alpha- and deltaproteobacterial species, and a dedicated (single-target) VPEID-CTERM/exosortase E system in alphaproteobacteria. Exosortase-related families XrtF in the class Flavobacteria and XrtG in Gram-positive bacteria mark distinctive conserved gene neighborhoods. A picture emerges of an ancient and now well-differentiated superfamily of deeply membrane-embedded protein-processing enzymes. Their target proteins are destined to transit cellular membranes during their biosynthesis, during which most undergo additional posttranslational modifications such as glycosylation.</p>},
	keywords = {Amino Acid Sequence, Aminoacyltransferases, Archaeal Proteins, Bacterial Proteins, Cell Membrane, Cysteine Endopeptidases, Gene Expression Regulation, Archaeal, Gene Expression Regulation, Bacterial, Gene Expression Regulation, Enzymologic, Molecular Sequence Data, Protein Processing, Post-Translational},
	issn = {1098-5530},
	doi = {10.1128/JB.06026-11},
	author = {Haft, Daniel H and Payne, Samuel H and Jeremy D Selengut}
}
