circularly permuted PDZ domain of C-terminal processing peptidase (CPP), a serine protease, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of CPP (also known as tail-specific protease, PRC protein, Protease Re, and Photosystem II D1 protein processing peptidase), and related domains. CPP belongs to the peptidase S41A family. It cleaves a C-terminal 11 residue peptide from the precursor form of penicillin-binding protein 3, and may have a role in protecting bacterium from thermal and osmotic stresses. In the plant chloroplast, the enzyme removes the C-terminal extension of the D1 polypeptide of photosystem II. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains and as well as those with circular permutations and domain swapping of beta-strands. The canonical PDZ domain contains six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2); arranged as A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F. This CPP-like PDZ domain is a circularly permuted PDZ domain which places beta-strand A on the C-terminus. Another permutation exists in the PDZ superfamily which places both beta-strands A and B on the C-terminus.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 55769541  22 GLTIAQRDDG-VFVQEVTQNSPAARTGvVKEGDQIVGA-TIYFDNLQSGEVTQLL----NTmghhTVGLKLHRKGDRSP 94
Cdd:cd06782   5 GIEIGKDDDGyLVVVSPIPGGPAEKAG-IKPGDVIVAVdGESVRGMSLDEVVKLLrgpkGT----KVKLTIRRGGEGEP 78

Periplasmic serine protease, S1-C subfamily, contain C-terminal PDZ domain [Posttranslational modification, protein turnover, chaperones];

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 55769541  28 RDDGVFVQEVTQNSPAARTGvVKEGDQIVGatiyFDNLQSGEVTQLLNTMGHHTVG----LKLHRKGDR 92
Cdd:COG0265 199 EPEGVLVARVEPGSPAAKAG-LRPGDVILA----VDGKPVTSARDLQRLLASLKPGdtvtLTVLRGGKE 262

circularly permuted PDZ domain of C-terminal processing peptidase (CPP), a serine protease, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of CPP (also known as tail-specific protease, PRC protein, Protease Re, and Photosystem II D1 protein processing peptidase), and related domains. CPP belongs to the peptidase S41A family. It cleaves a C-terminal 11 residue peptide from the precursor form of penicillin-binding protein 3, and may have a role in protecting bacterium from thermal and osmotic stresses. In the plant chloroplast, the enzyme removes the C-terminal extension of the D1 polypeptide of photosystem II. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains and as well as those with circular permutations and domain swapping of beta-strands. The canonical PDZ domain contains six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2); arranged as A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F. This CPP-like PDZ domain is a circularly permuted PDZ domain which places beta-strand A on the C-terminus. Another permutation exists in the PDZ superfamily which places both beta-strands A and B on the C-terminus.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 55769541  22 GLTIAQRDDG-VFVQEVTQNSPAARTGvVKEGDQIVGA-TIYFDNLQSGEVTQLL----NTmghhTVGLKLHRKGDRSP 94
Cdd:cd06782   5 GIEIGKDDDGyLVVVSPIPGGPAEKAG-IKPGDVIVAVdGESVRGMSLDEVVKLLrgpkGT----KVKLTIRRGGEGEP 78

PDZ domain 2 of PDZ domain-containing RING finger protein 4 (PDZRN4), PDZRN3-B, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 1 of PDZRN4, PDZRN3-B, and related domains. PDZRN4 (also known as ligand of numb protein X 4, and SEMACAP3-like protein) contains an N-terminal RING domain and two tandem repeat PDZ domains. It is involved in the progression of cancer, including human liver cancer and breast cancer, and may contribute to the tumorigenesis of rectal adenocarcinoma. Danio rerio PDZRN3-B may participate in neurogenesis: the first PDZ domain of Danio rerio Pdzrn3 interacts with Kidins220 (Kinase D-interacting substrate 220 kD, also named Ankyrin Repeat-Rich Membrane Spanning), a crucial mediator of signal transduction in neural tissues. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This PDZRN4-like family PDZ2 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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                ....*....|....*....|....*....|....*....|
gi 55769541  22 GLTIAQRDD-----GVFVQEVTQNSPAARTGVVKEGDQIV 56
Cdd:cd06716  18 GLTLCYRTDdeedtGIYVSEVDPNSIAAKDGRIREGDQIL 57

Periplasmic serine protease, S1-C subfamily, contain C-terminal PDZ domain [Posttranslational modification, protein turnover, chaperones];

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 55769541  28 RDDGVFVQEVTQNSPAARTGvVKEGDQIVGatiyFDNLQSGEVTQLLNTMGHHTVG----LKLHRKGDR 92
Cdd:COG0265 199 EPEGVLVARVEPGSPAAKAG-LRPGDVILA----VDGKPVTSARDLQRLLASLKPGdtvtLTVLRGGKE 262

PDZ domain 2 of Zonula Occludens-1 (ZO-1), ZO-2 and ZO-3, and related domains; form domain-swapping dimers; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 2 of ZO-1, -2, -3 and related domains. Zonula occludens proteins (ZO-1, ZO-2, ZO-3) are multi-PDZ domain proteins involved in the maintenance and biogenesis of multi-protein networks at the cytoplasmic surface of intercellular contacts in epithelial and endothelial cells. They have three N-terminal PDZ domains, PDZ1-3, followed by a Src homology-3 (SH3) domain and a guanylate kinase (GuK)-like domain. Among protein-protein interactions for all ZO proteins is the binding of the first PDZ domain (PDZ1) to the C-termini of claudins , and the homo- and hetero-dimerization of ZO-proteins via their second PDZ domain (PDZ2), which takes place by symmetrical domain swapping of the first two beta-strands of PDZ2. At the cell level, ZO-1 and ZO-2 are involved in polarity maintenance, gene transcription, cell proliferation, and tumor cell metastasis. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This ZO family PDZ2 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                        10        20        30
                ....*....|....*....|....*....|....*.
gi 55769541  20 SHGLTIAQRddgVFVQEVTQNSPAARTGVVKEGDQI 55
Cdd:cd06728  13 EYGLRLGSR---IFVKEITPDSLAAKDGNLQEGDII 45

circularly permuted second PDZ domain (PDZ2) of Escherichia coli periplasmic serine endoprotease DegP and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 2 of Escherichia coli DegP (also known as heat shock protein DegP and Protease Do), and related domains. DegP belongs to the HtrA family of housekeeping proteases. It acts as a protease, degrading transiently denatured and unfolded or misfolded proteins which accumulate in the periplasm following heat shock or other stress conditions, and as a molecular chaperone at low temperatures. DegP has two PDZ domains in addition to the protease domain; its PDZ1 domain is responsible for the identifying the distinct substrate sequences that affect degradation (degron) of the substrate sequence, and its PDZ2 domain is responsible for the combining with other DegP monomers to form a stable oligomer structure. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains and as well as those with circular permutations and domain swapping of beta-strands. The canonical PDZ domain contains six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2); arranged as A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F. This DegP family PDZ domain 2 is a circularly permuted PDZ domain which places beta-strand A on the C-terminus. Another permutation exists in the PDZ superfamily which places both beta-strands A and B on the C-terminus.

                        10        20        30
                ....*....|....*....|....*....|....*.
gi 55769541  23 LTIAQRDDGVFVQEVTQNSPAARTGvVKEGDQIVGA 58
Cdd:cd23084  11 VTDEDGGKGVVVTEVDPGSPAAQSG-LKKGDVIIGV 45

PDZ domain of synaptojanin-2-binding protein (SYNJ2BP), and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of SYNJ2BP, and related domains. SYNJ2BP (also known as mitochondrial outer membrane protein 25, OMP25) regulates endocytosis of activin type 2 receptor kinases through the Ral/RALBP1-dependent pathway and may be involved in suppression of activin-induced signal transduction. Binding partners of the SYNJ2BP PDZ domain include activin type II receptors (ActR-II), and SYNJ2. SYNJ2BP interacts with the PDZ binding motif of the Notch Delta-like ligand 1 (DLL1) and DLL4, promoting Delta-Notch signaling, and inhibiting sprouting angiogenesis. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This SYNJ2BP-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 55769541  29 DDGVFVQEVTQNSPAARTGVVKEGDQIV---GATIyfDNLQSGEVTQLLNTMGHHtVGLK 85
Cdd:cd06709  28 DSGIYVAKIKEDGAAAIDGRLQEGDKILeinGQSL--ENLTHQDAVELFRNAGED-VKLK 84

PDZ domain 1 of multi-PDZ-domain protein 1 (MUPP1) and PATJ (protein-associated tight junction), and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 1 of MUPP1 and PATJ, and related domains. MUPP1 and PATJ serve as scaffolding proteins linking different proteins and protein complexes involved in the organization of tight junctions and epithelial polarity. MUPP1 contains an L27 (Lin-2 and Lin-7 binding) domain and 13 PDZ domains. PATJ (also known as INAD-like) contains an L27 domain and ten PDZ domains. MUPP1 and PATJ share several binding partners, including junctional adhesion molecules (JAM), zonula occludens (ZO)-3, Pals1 (protein associated with Lin-7), Par (partitioning defective)-6 proteins, and nectins (adherence junction adhesion molecules). PATJ lacks 3 PDZ domains seen in MUPP1: PDZ6, 9, and 13; consequently, MUPP1 PDZ7 and 8 align with PATJ PDZ6 and 7; and MUPP1 PDZ domains 10-12 align with PATJ PDZ domains 8-10. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MUPP1-like family PDZ1 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 55769541  22 GLTIAQRDD-GVFVQEVTQNSPAARTGVVKEGDQI 55
Cdd:cd06689  34 GLKSENRGElGIFVQEIQPGSVAARDGRLKENDQI 68

PDZ domain 3 of multi-PDZ-domain protein 1 (MUPP1) and PATJ (protein-associated tight junction) and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 3 of MUPP1 and PATJ, and related domains. MUPP1 and PATJ serve as scaffolding proteins linking different proteins and protein complexes involved in the organization of tight junctions and epithelial polarity. MUPP1 contains an L27 (Lin-2 and Lin-7 binding) domain and 13 PDZ domains. PATJ (also known as INAD-like) contains an L27 domain and ten PDZ domains. MUPP1 and PATJ share several binding partners, including junctional adhesion molecules (JAM), zonula occludens (ZO)-3, Pals1 (protein associated with Lin-7), Par (partitioning defective)-6 proteins, and nectins (adherence junction adhesion molecules). PATJ lacks 3 PDZ domains seen in MUPP1: PDZ6, 9, and 13; consequently, MUPP1 PDZ7 and 8 align with PATJ PDZ6 and 7; and MUPP1 PDZ domains 10-12 align with PATJ PDZ domains 8-10. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MUPP1-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 55769541  22 GLTIA------QRDD--GVFVQEVTQNSPAARTGVVKEGDQIV---GATIY-FDNLQSGEVtqLLNTmgHHTVGLKLHR 88
Cdd:cd06791  15 GITIAgyvgekASGElsGIFVKSIIPGSAADQDGRIQVNDQIIavdGVNLQgFTNQEAVEV--LRNT--GQVVHLTLAR 89

PDZ domain 3 of Zonula Occludens-1 (ZO-1), homologs ZO-2 and ZO-3, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 3 of ZO-1, -2, -3 and related domains. Zonula occludens proteins (ZO-1, ZO-2, ZO-3) are multi-PDZ domain proteins involved in the maintenance and biogenesis of multi-protein networks at the cytoplasmic surface of intercellular contacts in epithelial and endothelial cells. They have three N-terminal PDZ domains, PDZ1-3, followed by a Src homology-3 (SH3) domain and a guanylate kinase (GuK)-like domain. Among protein-protein interactions for all ZO proteins is the binding of the first PDZ domain (PDZ1) to the C-termini of claudins , and the homo- and hetero-dimerization of ZO-proteins via their second PDZ domain (PDZ2), which takes place by symmetrical domain swapping of the first two beta-strands of PDZ2. At the cell level, ZO-1 and ZO-2 are involved in polarity maintenance, gene transcription, cell proliferation, and tumor cell metastasis. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This ZO family PDZ3 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 55769541  19 GSHGLTIAQRDD-GVFVQEVTQNSPAARTGvVKEGDQIVGA-TIYFDNLQSGEVTQLL 74
Cdd:cd06729  11 GSVGLRLAGGNDvGIFVAGVQEGSPAEKQG-LQEGDQILKVnGVDFRNLTREEAVLFL 67

PDZ domain 11 of MUPP1 of multi-PDZ-domain protein 1 (MUPP1), domain 9 of PATJ (protein-associated tight junction) and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain 11 of MUPP1, PDZ domain 9 of PATJ, and related domains. MUPP1 and PATJ serve as scaffolding proteins linking different proteins and protein complexes involved in the organization of tight junctions and epithelial polarity. MUPP1 contains an L27 (Lin-2 and Lin-7 binding) domain and 13 PDZ domains. PATJ (also known as INAD-like) contains an L27 domain and ten PDZ domains. MUPP1 and PATJ share several binding partners, including junctional adhesion molecules (JAM), zonula occludens (ZO)-3, Pals1 (protein associated with Lin-7), Par (partitioning defective)-6 proteins, and nectins (adherence junction adhesion molecules). PATJ lacks 3 PDZ domains seen in MUPP1: PDZ6, 9, and 13; consequently, MUPP1 PDZ7 and 8 align with PATJ PDZ6 and 7; and MUPP1 PDZ domains 10-12 align with PATJ PDZ domains 8-10. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This MUPP1-like family PDZ11 domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 55769541   7 TRELLLPNWQGSGshgLTIAQR--DDGVFVQEVTQNSPAARTGVVKEGDQI 55
Cdd:cd06674   5 TVELQKKPGRGLG---LSIVGKrnDTGVFVSDIVKGGAADADGRLMQGDQI 52

PDZ domain of densin, erbin, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of densin, erbin, and related domains. Densin (also known as leucine-rich repeat-containing protein 7, LRRC7, densin-180, protein LAP1) and erbin (also known as densin-180-like protein, Erbb2-interacting protein, protein LAP2) belong to the LAP (leucine-rich repeat and PDZ domain) family of scaffolding proteins that play roles in the maintenance of cell shape and apical-basal polarity. Densin and erbin are components of the excitatory postsynaptic compartment and are regulators of dendritic morphology and postsynaptic structure. The densin PDZ domain binds CaV1.3 alpha1 subunit, delta-catenin, and MAGUIN-1. Binding partners of the erbin PDZ domain include ErbB receptor tyrosine kinase ErbB2, HTLV-1 Tax1, Cav1.3 Ca2+channels, and constituents of the cadherin:catenin cell adhesion complex, in particular delta-catenin, p0071 and ARVCF. The erbin PDZ domain binds Smad3, a transductor of the TGFbeta pathway, possibly by a novel interface of binding. Erbin and two other LAP proteins (scribble and lano) redundantly regulate epithelial polarity and apical adhesion complex. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This densin and erbin-like family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged as beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 55769541  17 GSGSHGLTIAQRDDGVFVQEVTQNSPAArtGVVKEGDQIVGAT-IYFDNLQSGEVTQLLNTMGhHTVGLKLHR 88
Cdd:cd06749  18 GIGSQGNPFRPDDDGIFVTKVQPDGPAS--KLLQPGDKILEVNgYDFVNIEHGQAVSLLKSFQ-NTVDLVVER 87

circularly permuted PDZ domain of high-temperature requirement factor A (HtrA) family serine proteases and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of HtrA family serine proteases including human HtrA1, HtrA2 (mitochondrial), HtrA3, and HtrA4, and related domains. These proteases are key enzymes associated with pregnancy. Their diverse biological functions include cell growth proliferation, migration and apoptosis. They are also implicated in disorders including Alzheimer's, Parkinson's, arthritis and cancer. HtrA1 (also known as high-temperature requirement A serine peptidase 1, L56, and serine protease 11) substrates include extracellular matrix proteins, proteoglycans, and insulin-like growth factor (IGF)-binding proteins. HtrA1 also inhibits signaling by members of the transforming growth factor beta (TGF-beta) family. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping of beta-strands. The canonical PDZ domain contains six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2); arranged as A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F. This HtrA-like PDZ domain is a circularly permuted PDZ domain which places beta-strand A on the C-terminus. Another permutation exists in the PDZ superfamily which places both beta-strands A and B on the C-terminus.

                        10        20
                ....*....|....*....|....*.
gi 55769541  31 GVFVQEVTQNSPAARTGvVKEGDQIV 56
Cdd:cd06785  32 GVYVHKVIPGSPAQRAG-LKDGDVII 56

permuted PDZ domain of Deg/high-temperature requirement factor A (HtrA) family of housekeeping serine proteases and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of Deg/HtrA-type serine proteases that participate in folding and degradation of aberrant proteins, and in processing and maturation of native proteins. Typically, these proteases have an N-terminal serine protease domain and at least one C-terminal PDZ domain that recognizes substrates, and in some cases activates the protease function. An exception is yeast Nma11p which has two protease domains and four PDZ domains; its N-terminal half is comprised of a protease domain, followed by two PDZ domains, and its C-terminal half has a similar domain arrangement. HtrA-type proteases include the human HtrA1-4 and MBTPS2, tricorn protease, DegS, DegP and C-terminal processing peptidase, cyanobacterial serine proteases Hhoa, HhoB, and HtrA, and yeast Nma11p. PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-termini of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains and as well as those with circular permutations and domain swapping of beta-strands. The canonical PDZ domain contains six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2); arranged as A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F. This Deg/HtrA family PDZ domain is a circularly permuted PDZ domain which places beta-strand A at the C-terminus. Another permutation exists in the PDZ superfamily which places both beta-strands A and B on the C-terminus.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 55769541  29 DDGVFVQEVTQNSPAARTGvVKEGDQIVGatiyFDNLQSGEVTQLLNTMGHHTVG----LKLHRKGDR 92
Cdd:cd06779  24 NRGVLVAEVIPGSPAAKAG-LKEGDVILS----VNGKPVTSFNDLRAALDTKKPGdslnLTILRDGKT 86

PDZ domain of Rap guanine nucleotide exchange factor 2 and Rap guanine nucleotide exchange factor 6, and related domains; PDZ (PSD-95 (Postsynaptic density protein 95), Dlg (Discs large protein), and ZO-1 (Zonula occludens-1)) domain of Rap guanine nucleotide exchange factor 2 (RapGEF2, also named RA-GEF-1, PDZ-GEF1, CNrasGEF and nRapGEP) and Rap guanine nucleotide exchange factor 6 (RapGEF6, also named RA-GEF-2 and PDZ-GEF2). RapGEF2 and RapGEF6 constitute a subfamily of guanine nucleotide exchange factors (GEFs) for RAP small GTPases that is characterized by the possession of the PDZ and Ras/Rap-associating domains. They activate Rap small GTPases, by catalyzing the release of GDP from the inactive GDP-bound forms, thereby accelerating GTP loading to yield the active GTP-bound forms. The PDZ domain of RapGEF6 (also known as PDZ-GEF2) binds junctional adhesion molecule A (JAM-A). PDZ domains usually bind in a sequence-specific manner to short peptide sequences located at the C-terminal end of their partner proteins (known as PDZ binding motifs). The PDZ superfamily includes canonical PDZ domains as well as those with circular permutations and domain swapping mediated by beta-strands. This RapGEF2 and RapGEF6 family domain is a canonical PDZ domain containing six beta-strands A-F and two alpha-helices (alpha-helix 1 and 2), arranged in the order: beta-strands A, B, C, alpha-helix 1, beta-strands D, E, alpha-helix 2 and beta-strand F.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 55769541  27 QRDDGVFVQEVTQNSPAARTGvVKEGDQIV---GATiyFDNLQSGEVTQLLNTMGHHTVGLK 85
Cdd:cd06755  23 EKGFGIFVSKVEKGSKAAEAG-LKRGDQILevnGQN--FENITLKKALEILRNNTHLSITVK 81