TY - JOUR T1 - Archaeosortases and exosortases are widely distributed systems linking membrane transit with posttranslational modification. JF - J Bacteriol Y1 - 2012 A1 - Haft, Daniel H A1 - Payne, Samuel H A1 - Selengut, Jeremy D KW - Amino Acid Sequence KW - Aminoacyltransferases KW - Archaeal Proteins KW - Bacterial Proteins KW - Cell Membrane KW - Cysteine Endopeptidases KW - Gene Expression Regulation, Archaeal KW - Gene Expression Regulation, Bacterial KW - Gene Expression Regulation, Enzymologic KW - Molecular Sequence Data KW - Protein Processing, Post-Translational AB -

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.

VL - 194 CP - 1 M3 - 10.1128/JB.06026-11 ER - TY - JOUR T1 - Archaeosortases and exosortases are widely distributed systems linking membrane transit with posttranslational modification JF - Journal of bacteriologyJournal of bacteriology Y1 - 2012 A1 - Haft, Daniel H. A1 - Payne, Samuel H. A1 - J. Selengut KW - Amino Acid Sequence KW - Aminoacyltransferases KW - Archaeal Proteins KW - Bacterial Proteins KW - Cell Membrane KW - Cysteine Endopeptidases KW - Gene Expression Regulation, Archaeal KW - Gene Expression Regulation, Bacterial KW - Gene Expression Regulation, Enzymologic KW - Molecular Sequence Data KW - Protein Processing, Post-Translational AB - 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. VL - 194 N1 - http://www.ncbi.nlm.nih.gov/pubmed/22037399?dopt=Abstract ER - TY - JOUR T1 - Transcriptional profiling of the hyperthermophilic methanarchaeon Methanococcus jannaschii in response to lethal heat and non-lethal cold shock. JF - Environ Microbiol Y1 - 2005 A1 - Boonyaratanakornkit, Boonchai B A1 - Simpson, Anjana J A1 - Whitehead, Timothy A A1 - Fraser, Claire M A1 - el-Sayed, Najib M A A1 - Clark, Douglas S KW - Adaptation, Physiological KW - Archaeal Proteins KW - Cold Temperature KW - Gene Expression Profiling KW - Gene Expression Regulation, Archaeal KW - Heat-Shock Proteins KW - Hot Temperature KW - Methanococcus KW - Temperature KW - Transcription, Genetic AB -

Temperature shock of the hyperthermophilic methanarchaeon Methanococcus jannaschii from its optimal growth temperature of 85 degrees C to 65 degrees C and 95 degrees C resulted in different transcriptional responses characteristic of both the direction of shock (heat or cold shock) and whether the shock was lethal. Specific outcomes of lethal heat shock to 95 degrees C included upregulation of genes encoding chaperones, and downregulation of genes encoding subunits of the H+ transporting ATP synthase. A gene encoding an alpha subunit of a putative prefoldin was also upregulated, which may comprise a novel element in the protein processing pathway in M. jannaschii. Very different responses were observed upon cold shock to 65 degrees C. These included upregulation of a gene encoding an RNA helicase and other genes involved in transcription and translation, and upregulation of genes coding for proteases and transport proteins. Also upregulated was a gene that codes for an 18 kDa FKBP-type PPIase, which may facilitate protein folding at low temperatures. Transcriptional profiling also revealed several hypothetical proteins that respond to temperature stress conditions.

VL - 7 CP - 6 M3 - 10.1111/j.1462-2920.2005.00751.x ER -