PA: Protease-associated (PA) domain. The PA domain is an insert domain in a diverse fraction of proteases. The significance of the PA domain to many of the proteins in which it is inserted is undetermined. It may be a protein-protein interaction domain. At peptidase active sites, the PA domain may participate in substrate binding and/or promoting conformational changes, which influence the stability and accessibility of the site to substrate. Proteins into which the PA domain is inserted include the following: i) various signal peptide peptidases including, hSPPL2a and 2b which catalyze the intramembrane proteolysis of tumor necrosis factor alpha, ii) various proteins containing a C3H2C3 RING finger including, Arabidopsis ReMembR-H2 protein and various E3 ubiquitin ligases such as human GRAIL (gene related to anergy in lymphocytes), iii) EDEM3 (ER-degradation-enhancing mannosidase-like 3 protein), iv) various plant vacuolar sorting receptors such as Pisum sativum BP-80, v) glutamate carboxypeptidase II (GCPII), vi) yeast aminopeptidase Y, vii) Vibrio metschnikovii VapT, a sodium dodecyl sulfate (SDS) resistant extracellular alkaline serine protease, viii) lactocepin (a cell envelope-associated protease from Lactobacillus paracasei subsp. paracasei NCDO 151), ix) various subtilisin-like proteases such as melon Cucumisin, and x) human TfR (transferrin receptor) 1 and 2.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564347589  51 DFGGIFHTRYEQIHLVPAEPPEACGELSNGFFIQDQIALVER-------------------------------------- 92
Cdd:cd02127    1 DFGTIFNTRYKHVPLVPADPLEACEELRNIHDINGNIALIERggcsfltkainaqkagalaviitdvnndsdeyyvemiq 80

                         90       100       110
                 ....*....|....*....|....*....|....*...
gi 564347589  93 ------------------GYMIRRSLEQHGLPWAIISI 112
Cdd:cd02127   81 ddssrradipaafllgknGYMIRKTLERLGLPYAIINI 118

PA_hPAP21_like: Protease-associated domain containing proteins like the human secreted glycoprotein hPAP21 (human protease-associated domain-containing protein, 21kDa). This group contains various PA domain-containing proteins similar to hPAP21. Complex N-glycosylation may be required for the secretion of hPAP21. The significance of the PA domain to hPAP21 has not been ascertained. It may be a protein-protein interaction domain. At peptidase active sites, the PA domain may participate in substrate binding and/or promoting conformational changes, which influence the stability and accessibility of the site to substrate.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564347589  51 DFGGIFHTRYEQIHLVPAEPPEACGELSNGFFIQDQIALVER-------------------------------------- 92
Cdd:cd02127    1 DFGTIFNTRYKHVPLVPADPLEACEELRNIHDINGNIALIERggcsfltkainaqkagalaviitdvnndsdeyyvemiq 80

                         90       100       110
                 ....*....|....*....|....*....|....*...
gi 564347589  93 ------------------GYMIRRSLEQHGLPWAIISI 112
Cdd:cd02127   81 ddssrradipaafllgknGYMIRKTLERLGLPYAIINI 118

PA_hPAP21_like: Protease-associated domain containing proteins like the human secreted glycoprotein hPAP21 (human protease-associated domain-containing protein, 21kDa). This group contains various PA domain-containing proteins similar to hPAP21. Complex N-glycosylation may be required for the secretion of hPAP21. The significance of the PA domain to hPAP21 has not been ascertained. It may be a protein-protein interaction domain. At peptidase active sites, the PA domain may participate in substrate binding and/or promoting conformational changes, which influence the stability and accessibility of the site to substrate.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564347589  51 DFGGIFHTRYEQIHLVPAEPPEACGELSNGFFIQDQIALVER-------------------------------------- 92
Cdd:cd02127    1 DFGTIFNTRYKHVPLVPADPLEACEELRNIHDINGNIALIERggcsfltkainaqkagalaviitdvnndsdeyyvemiq 80

                         90       100       110
                 ....*....|....*....|....*....|....*...
gi 564347589  93 ------------------GYMIRRSLEQHGLPWAIISI 112
Cdd:cd02127   81 ddssrradipaafllgknGYMIRKTLERLGLPYAIINI 118