9.B.2 The Integral Membrane CAAX Protease-2 (CAAX Protease2) Family
The CAAX Protease2 family includes members that are similar in many ways to the CAAX protease family (9.B.1), but the sequence divergence is extensive. The latter proteins do not bring up members of the former family in PSI-BLAST searches, and vise versa. These proteins bring up 3.A.1.115.2 (NatB, the membrane constituent of the Na exporting ABC system, NatAB) and 3.A.1.110.1 (MceF, with 7 TMSs that may be a CAAX protease and not part of the transporter). These proteins may have a 2 + 2 + 2 TMS topology. Sortases (TC# 9.B.297) are distantly related to members of the CAAX protease-2.1 subfamily, and some of these are listed under TC subfamily 9.B.2.14 (Haft 2024).
References:
CAAX protease2 of 302aas and 8 TMSs
Chlamydiae
CAAX protease2 of Parachlamydia acanthamoebae (F8KZQ2)
CAAX protease involved in immunity against bacteriocins (Pei and Grishin 2001).
Firmicutes
CAAX protease of Streptococcus pyogenes
CAAX protease of 233 aas.
Algae (Cryptophyta)
CAAX protease of Guillardia theta
Abortive infection domain protein, Abi of 193 aas. The C-terminal region has the Abi domain.
Proteobacteria
Putative CAAX protease of Marinobacter aquaeolei (Marinobacter hydrocarbonoclasticus)
Abortive infection-like protein of 323 aas with a C-terminal Abi domain.
Algae (Rhodophyta)
Abi protein of Galdieria sulphuraria
Abi domain-containing protein of 305 aas and 10 TMSs.
Proteobacteria
Abi protein of Koribacter versatilis
Abi domain-containing protein of 400 aas and 10 TMSs.
Red algae (Rhodophyta)
Abi protein of Galdieria sufphuraria
LsrS, a 229 aas CAAX peptidase that is required for receptor function for the killing activity of the lantibiiotics Smb and nisin (Biswas and Biswas 2014). The peptidase activity is not required for receptor function.
Firmicutes
LsrS of Streptococcus mutans
CAAX protease of 223 aas and 7 TMSs
CAAX protease of Chlamydomonas reinhardtii
Putative CAAX protease of 215 aas and 6 TMSs
CAAX protease of Lactobacillus rhamnosus
Membrane peptidase, YdiL, of 293 aas.
YdiL of Capsicum annuum
CAAX protease2 of 258aas and 7 or 8 TMSs.
Chlamydiae
CAAX protease2 of Chlamydophila pecorum (F4DIL5)
Intramembrane metaloprotease of 195 aas and 7 TMSs.
Protease of Lactobacillus xiangfangensis
CPBP protease family member of 225 aas and 6 TMSs.
Protease of Bacillus cereus
CPBP integral membrane metaloprotease (sortase?) family member of 242 aas and 6 or 7 TMSs.
Protease of Dokdonella koreensis
CAAX amino terminal protease family protein of 351 aas and 8 TMSs.
CAAX protease of Clostridium methylpentosum
Uncharacterized putative integral membrane proteinof 240 aas and 6 TMSs.
UP of Mycobacterium tuberculosis
CAAX protease of 357 aas and 7 TMSs.
CAAX protease of Lokiarchaeum sp.
Uncharacterized putative peptidase of 163 aas and 5 putative TMSs.
UP of Candidatus Thorarchaeota archaeon AB_25 (marine sediment metagenome)
Uncharacterized protein of 325 aas and 8 TMSs
UP of Candidatus Thorarchaeota archaeon AB_25 (marine sedimet metagenome)
CPBP family intramembrane metalloprotease of 1141 aas and 7 TMSs, all at the C-terminus of the protein.
Protease of Bifidobacterium indicum
JDVT-CTERM system glutamic-type intramembrane protease of 163 aas and 5 TMSs. It may not be full length.
Protease of Noviherbaspirillum sp.
CAAX protease2 of 256aas and 7 or 8 TMSs
Chlamydiae
CAAX protease of Chlamydia trachomatis (Q3KMA8)
Uncharacterized protein of 420 aas
Euryarchaea
UP of Methanothermobacter thermautotrophicus
CAAX protease2 of 239aas and 5 or 6 TMSs
Bacteroidetes
CAAX protease2 of Porphyromonas catoniae (L1NER1)
Me2+-dependent protease of 303aas and 8 TMSs
Cyanobacteria
Protease of Acaryochloris marina (B0C1B4)
CAAX protease2 of 373aas and 11 TMSs
Archaea
CAAX protease2 of Natronolimnobius innermongolicus (L9XEM0)
CAAX protease2 of 230aas and 6 TMSs
Firmicutes
CAAX protease2 of Sporosarcina newyorkensis (F9DWD5)
MceF CAAX Protease
Bacteria
MceF of Klebsiella pneumoniae
The CPBP family intramembrane metalloprotease domain-containing protein of 468 aas and 7 TMSs.
CPBP protease of Methanomassiliicoccus luminyensis
Uncharacterized CPBP family intramembrane metalloprotease domain-containing protein of 366 aas and 8 TMSs.
UP of Aciduliprofundum boonei
Uncharacterized CPBP family intramembrane metalloprotease domain-containing protein of 369 aas and 7 TMSs.
UP of Candidatus Methanomethylophilus alvus
Uncharacterized CPBP family intramembrane metalloprotease domain-containing protein of 301 aas and 7 TMSs.
UP of methanogenic archaeon ISO4-H5
Uncharacterized CPBP family intramembrane metalloprotease domain-containing protein of 312 aas and 7 TMSs.
UP of Candidatus Nitrosopelagicus brevis
CPBP family intramembrane metalloprotease of 213 aas
Protease of Pseudoalteromonas
CPBP/CAAX family intramembrane metaloprotease of 221 aas and 6 TMSs.
Metaloprotease of Microbulbifer aggregans
CAAX amino terminal protease self-immunity of 194 aas and 6 TMSs in a 2 + 2 + 2 arrangement.
CAAX protease of Lokiarchaeum sp. GC14_75 (marine sediment metagenome)
Uncharacterized protein of 207 aas and 6 TMSs
UP of Candidatus Peribacter riflensis
Metaloprotease of 213 aas and 6 TMSs
Metaloprotease of Lewinella cohaerens
Putative CAAX protease of 496 aas and 7 TMSs in a 1 (N-terminal) + 6 (C-terminal) TMS arrangement. The gene for this protein is adjacent to an ABC transporter (TC# 3.A.1.128.10), probably specific for a sporulation killing factor, SkfB (Grell et al. 2018). This protease may therefore function to process SkfB.
Protease of Bacillus stratosphericus
Myxosortase X, MXAN-2755 or MrtX of 239 aas with 4 to 6 TMSs in a possibly 2 + 1 + 2 + 1 arrangement. It is a CPBP family intramembrane metalloprotease. Other myxosortases include: MrtC (TC# 9.B.2.14.2), MrtP (TC# 9.B.2.14.3), MrtJ, MrtS and MrtA. All of these systems are present in Myxococcus xanthus (Haft 2024).
MrtX of Myxococcus xanthus
MrtC sortase; glutamic-type intramembrane protease of 247 aas and 6 TMSs.
MrtC of Polyangiaceae bacterium
Myxosortase MrtP OF 361 aas and 7 putative TMSs in a 3 (N-terminal) + 4 (C-terminal) TMS arrangement.
MrtP of Lujinxingia vulgaris
CAAX protease of 274 aas
Red algae (Rhodophyta)
CAAX protease of Galdieria sulphuraria
CAAX amino terminal protease of 306 aas and 8 TMSs.
Firmicutes
CAAX protease of Desulfitobacterium metallireducens
CAAX protease of 274 aas and 8 TMSs.
Chloroflexi
CAAX protease of Anaerolnea thermopila
Putative transporter of 206 aas and 6 TMSs.
Proteobacteeria
Putative transporter of Klebsiella pneumoniae
Uncharacterized protein of 217 aas and 6 TMSs.
Proteobacteria
UP of Vibrio fischeri
Putative Brp/Blh family of β-carotene monooxygenases of 221 aas and 6 TMSs
Bacteroidetes
UP of Psychroflexus torquis
Uncharacterized protein of 230 aas and 6 TMSs
Proteobacteria
UP of Deftia acidovorans
Uncharacterized protein of 206 aas and 6 TMSs
Firmicutes
UP of Acidaminococcus intestini
Uncharacterized protein of 215 aas and 6 TMSs
Proteobacteria
UP of Salmonella schwarzengrund
Uncharacterized protein of 215 aas and 6 TMSs
Firmicutes
UP of Megamonas hypermegale
Uncharacterized protein of 209 aas and 5 or 6 TMSs
Proteobacteria
UP of Geobacter sp.
Uncharacterized protein of 181 aas and 5 putative TMSs.
Proteobacteria
UP of an uncultured Desulfobacterium
Uncharacterized protein of 228 aas and 6 TMSs
Proteobacteria
UP of Parvibaculum lavamentivorans
Uncharacterized protein of 181 aas and 5 TMSs.
Proteobacteria
UP of Thioalkalimicrobium cyclicum
Uncharacterized protein of 228 aas and 7 TMSs
Proteobacteria
UP of Phyllobacterium sp. YR531
Uncharacterized protein of 172 aas and 5 TMSs.
Euryarchaea
UP of Methanococcus maripaludis
Uncharacterized protein of 227 aas and 6 TMSs
Proteobacteria
UP of Rhizobium sp.
Uncharacterized protein of 213 aas and 6 TMSs. This protein is the only member of its subfamily, but a protein from Zymophilus raffinosivorans (gi# 518382944), not in UniProt as of 5/5/14, shows similarity to it as well as members of subfamily 9.B.2.5.
Proteobacteria
UP of Octadecabacter antarcticus
Putative CPBP family membrane metaloprotease of 195 aas and 7 TMSs.
Protease of Streptococcus ferus
Putative membrane metaloprotease of 193 aas and 6 TMSs.
Protease of Candidatus Saccharibacteria bacterium
Uncharacterized protein of 329 aas and 6 TMSs in a 1 + 2 + 3 TMS arrangement
UP of Natronorubrum tibetense