C2 domain of Perforin; Perforin contains a single copy of a C2 domain in its C-terminus and plays a role in lymphocyte-mediated cytotoxicity. Mutations in perforin leads to familial hemophagocytic lymphohistiocytosis type 2. The function of perforin is calcium dependent and the C2 domain is thought to confer this binding to target cell membranes. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 388 SPHNPCQCVCHGSAVTNQDCCPRQRGLAHLEVMNFQASGLWGDSFTKTDAYLKVFFGGQELRVSTVWNDNNPKWMTRLDF 467
Cdd:cd04032     1 SARDNCPCVCSSSPNVNSNCCPTRRGLATLTVTVLRATGLWGDYFTSTDGYVKVFFGGQEKRTEVIWNNNNPRWNATFDF 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*..
gi 2168437580 468 GDVILSTGGPLRVQVWDQDHGWDDDLLGTCDQNPRSGLHEVRCGLSH 514
Cdd:cd04032    81 GSVELSPGGKLRFEVWDRDNGWDDDLLGTCSVVPEAGVHEDSCQLNH 127

C2 domain of Perforin; Perforin contains a single copy of a C2 domain in its C-terminus and plays a role in lymphocyte-mediated cytotoxicity. Mutations in perforin leads to familial hemophagocytic lymphohistiocytosis type 2. The function of perforin is calcium dependent and the C2 domain is thought to confer this binding to target cell membranes. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 388 SPHNPCQCVCHGSAVTNQDCCPRQRGLAHLEVMNFQASGLWGDSFTKTDAYLKVFFGGQELRVSTVWNDNNPKWMTRLDF 467
Cdd:cd04032     1 SARDNCPCVCSSSPNVNSNCCPTRRGLATLTVTVLRATGLWGDYFTSTDGYVKVFFGGQEKRTEVIWNNNNPRWNATFDF 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*..
gi 2168437580 468 GDVILSTGGPLRVQVWDQDHGWDDDLLGTCDQNPRSGLHEVRCGLSH 514
Cdd:cd04032    81 GSVELSPGGKLRFEVWDRDNGWDDDLLGTCSVVPEAGVHEDSCQLNH 127

MAC/Perforin domain; The membrane-attack complex (MAC) of the complement system forms transmembrane channels. These channels disrupt the phospholipid bilayer of target cells, leading to cell lysis and death. A number of proteins participate in the assembly of the MAC. Freshly activated C5b binds to C6 to form a C5b-6 complex, then to C7 forming the C5b-7 complex. The C5b-7 complex binds to C8, which is composed of three chains (alpha, beta, and gamma), thus forming the C5b-8 complex. C5b-8 subsequently binds to C9 and acts as a catalyst in the polymerization of C9. Active MAC has a subunit composition of C5b-C6-C7-C8-C9{n}. Perforin is a protein found in cytolytic T-cell and killer cells. In the presence of calcium, perforin polymerizes into transmembrane tubules and is capable of lysing, non-specifically, a variety of target cells. There are a number of regions of similarity in the sequences of complement components C6, C7, C8-alpha, C8-beta, C9 and perforin. The X-ray crystal structure of a MACPF domain reveals that it shares a common fold with bacterial cholesterol dependent cytolysins (pfam01289) such as perfringolysin O. Three key pieces of evidence suggests that MACPF domains and CDCs are homologous: Functional similarity (pore formation), conservation of three glycine residues at a hinge in both families and conservation of a complex core fold.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 149 GSHSHMANFA--AQKTFHDQYSFSTDLVECRFYSSHLV--HSPPLHPNFQRVVRDLPPDFNTSTEADYLRLISNYGTHFI 224
Cdd:pfam01823   1 GSFSASSEFKkmSDKSKQKKKSLIISKSTCSLYQFTLKrsNKLQLSDEFLQALSDLPDNYDYAAKATYIQFFDKYGTHYI 80

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 225 RSMELGGRISALTALRTCELALDGLGAKEVEDCLAVEAQVSISgradfSSEFKACEEKKKHHKIATSFHQAYRERFSEIV 304
Cdd:pfam01823  81 TSVTLGGKIVYVLKLDKSQLEDLKLKGEDVKICLSASAGASIG-----SVNLKGCSKNSSSTKEKKSFNQEIESSITLVI 155

                         170       180       190       200       210       220
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2168437580 305 GGhhtsvsdLLFGDQAGPEQFSAWVASLLDRPSLVDYTLEPLHVLLESQDPRREALRQAVSKY 367
Cdd:pfam01823 156 GG-------TPESIDDDSKTYSDWAESVKDNPMPIDFELTPISELLKGVPLKKENLRKALEEY 211

C2 domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 416 HLEVMNFQASGL-WGDSFTKTDAYLKVFF--GGQELRVSTVWNDNNPKWMTRLDFgDVILSTGGPLRVQVWDQDHGWDDD 492
Cdd:pfam00168   2 RLTVTVIEAKNLpPKDGNGTSDPYVKVYLldGKQKKKTKVVKNTLNPVWNETFTF-SVPDPENAVLEIEVYDYDRFGRDD 80

                  ....*
gi 2168437580 493 LLGTC 497
Cdd:pfam00168  81 FIGEV 85

C2 domain of Perforin; Perforin contains a single copy of a C2 domain in its C-terminus and plays a role in lymphocyte-mediated cytotoxicity. Mutations in perforin leads to familial hemophagocytic lymphohistiocytosis type 2. The function of perforin is calcium dependent and the C2 domain is thought to confer this binding to target cell membranes. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 388 SPHNPCQCVCHGSAVTNQDCCPRQRGLAHLEVMNFQASGLWGDSFTKTDAYLKVFFGGQELRVSTVWNDNNPKWMTRLDF 467
Cdd:cd04032     1 SARDNCPCVCSSSPNVNSNCCPTRRGLATLTVTVLRATGLWGDYFTSTDGYVKVFFGGQEKRTEVIWNNNNPRWNATFDF 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*..
gi 2168437580 468 GDVILSTGGPLRVQVWDQDHGWDDDLLGTCDQNPRSGLHEVRCGLSH 514
Cdd:cd04032    81 GSVELSPGGKLRFEVWDRDNGWDDDLLGTCSVVPEAGVHEDSCQLNH 127

MAC/Perforin domain; The membrane-attack complex (MAC) of the complement system forms transmembrane channels. These channels disrupt the phospholipid bilayer of target cells, leading to cell lysis and death. A number of proteins participate in the assembly of the MAC. Freshly activated C5b binds to C6 to form a C5b-6 complex, then to C7 forming the C5b-7 complex. The C5b-7 complex binds to C8, which is composed of three chains (alpha, beta, and gamma), thus forming the C5b-8 complex. C5b-8 subsequently binds to C9 and acts as a catalyst in the polymerization of C9. Active MAC has a subunit composition of C5b-C6-C7-C8-C9{n}. Perforin is a protein found in cytolytic T-cell and killer cells. In the presence of calcium, perforin polymerizes into transmembrane tubules and is capable of lysing, non-specifically, a variety of target cells. There are a number of regions of similarity in the sequences of complement components C6, C7, C8-alpha, C8-beta, C9 and perforin. The X-ray crystal structure of a MACPF domain reveals that it shares a common fold with bacterial cholesterol dependent cytolysins (pfam01289) such as perfringolysin O. Three key pieces of evidence suggests that MACPF domains and CDCs are homologous: Functional similarity (pore formation), conservation of three glycine residues at a hinge in both families and conservation of a complex core fold.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 149 GSHSHMANFA--AQKTFHDQYSFSTDLVECRFYSSHLV--HSPPLHPNFQRVVRDLPPDFNTSTEADYLRLISNYGTHFI 224
Cdd:pfam01823   1 GSFSASSEFKkmSDKSKQKKKSLIISKSTCSLYQFTLKrsNKLQLSDEFLQALSDLPDNYDYAAKATYIQFFDKYGTHYI 80

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 225 RSMELGGRISALTALRTCELALDGLGAKEVEDCLAVEAQVSISgradfSSEFKACEEKKKHHKIATSFHQAYRERFSEIV 304
Cdd:pfam01823  81 TSVTLGGKIVYVLKLDKSQLEDLKLKGEDVKICLSASAGASIG-----SVNLKGCSKNSSSTKEKKSFNQEIESSITLVI 155

                         170       180       190       200       210       220
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2168437580 305 GGhhtsvsdLLFGDQAGPEQFSAWVASLLDRPSLVDYTLEPLHVLLESQDPRREALRQAVSKY 367
Cdd:pfam01823 156 GG-------TPESIDDDSKTYSDWAESVKDNPMPIDFELTPISELLKGVPLKKENLRKALEEY 211

C2 domain; The C2 domain was first identified in PKC. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 417 LEVMNFQASGL-WGDSFTKTDAYLKVFFGGQELRVS-TVWNDNNPKWMTRLDFgDVILSTGGPLRVQVWDQDHGWDDDLL 494
Cdd:cd00030     1 LRVTVIEARNLpAKDLNGKSDPYVKVSLGGKQKFKTkVVKNTLNPVWNETFEF-PVLDPESDTLTVEVWDKDRFSKDDFL 79

                  ...
gi 2168437580 495 GTC 497
Cdd:cd00030    80 GEV 82

C2 domain third repeat in Ferlin; Ferlins are involved in vesicle fusion events. Ferlins and other proteins, such as Synaptotagmins, are implicated in facilitating the fusion process when cell membranes fuse together. There are six known human Ferlins: Dysferlin (Fer1L1), Otoferlin (Fer1L2), Myoferlin (Fer1L3), Fer1L4, Fer1L5, and Fer1L6. Defects in these genes can lead to a wide range of diseases including muscular dystrophy (dysferlin), deafness (otoferlin), and infertility (fer-1, fertilization factor-1). Structurally they have 6 tandem C2 domains, designated as (C2A-C2F) and a single C-terminal transmembrane domain, though there is a new study that disputes this and claims that there are actually 7 tandem C2 domains with another C2 domain inserted between C2D and C2E. In a subset of them (Dysferlin, Myoferlin, and Fer1) there is an additional conserved domain called DysF. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the third C2 repeat, C2C, and has a type-II topology.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2168437580 436 DAYLKVFFGGQELRVSTVWNDNNPKWMTRLDFGDVILSTGGPLRVQVWDQDHGWDDDLLGT 496
Cdd:cd04018    36 DPYVEVSFAGQKVKTSVKKNSYNPEWNEQIVFPEMFPPLCERIKIQIRDWDRVGNDDVIGT 96

C2 domain first repeat present in Synaptotagmin-like proteins; Synaptotagmin is a membrane-trafficking protein characterized by a N-terminal transmembrane region, a linker, and 2 C-terminal C2 domains. Previously all synaptotagmins were thought to be calcium sensors in the regulation of neurotransmitter release and hormone secretion, but it has been shown that not all of them bind calcium. Of the 17 identified synaptotagmins only 8 bind calcium (1-3, 5-7, 9, 10). The function of the two C2 domains that bind calcium are: regulating the fusion step of synaptic vesicle exocytosis (C2A) and binding to phosphatidyl-inositol-3,4,5-triphosphate (PIP3) in the absence of calcium ions and to phosphatidylinositol bisphosphate (PIP2) in their presence (C2B). C2B also regulates also the recycling step of synaptic vesicles. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the first C2 repeat, C2A, and has a type-I topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 433 TKTDAYLKVFFGGQELRVSTVWNDNNPKWMTRLDFgdVILSTGGP-LRVQVWDQDHGWDDDLLGTCD-------QNPRSG 504
Cdd:cd04024    22 GKSDPYAILSVGAQRFKTQTIPNTLNPKWNYWCEF--PIFSAQNQlLKLILWDKDRFAGKDYLGEFDialeevfADGKTG 99

                          90       100
                  ....*....|....*....|....*...
gi 2168437580 505 -------LHEVRCG---LSHG--HLRFS 520
Cdd:cd04024   100 qsdkwitLKSTRPGktsVVSGeiHLQFS 127

C2 domain present in Arf GTPase Activating Proteins (GAP); ArfGAP is a GTPase activating protein which regulates the ADP ribosylation factor Arf, a member of the Ras superfamily of GTP-binding proteins. The GTP-bound form of Arf is involved in Golgi morphology and is involved in recruiting coat proteins. ArfGAP is responsible for the GDP-bound form of Arf which is necessary for uncoating the membrane and allowing the Golgi to fuse with an acceptor compartment. These proteins contain an N-terminal ArfGAP domain containing the characteristic zinc finger motif (Cys-x2-Cys-x(16,17)-x2-Cys) and C-terminal C2 domain. C2 domains were first identified in Protein Kinase C (PKC). C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 2168437580 432 FTKTDAYLKVFFGGQELRVSTVWNDNNPKWMTRLDFGdvILSTGGPLRVQVWDQDHGWDDDLLG 495
Cdd:cd04038    19 FTSSDPYVVLTLGNQKVKTRVIKKNLNPVWNEELTLS--VPNPMAPLKLEVFDKDTFSKDDSMG 80

C2 domain second repeat in Copine; There are 2 copies of the C2 domain present in copine, a protein involved in membrane trafficking, protein-protein interactions, and perhaps even cell division and growth. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 419 VMNFQASGLWG-DSFTKTDAYLKVFFGGQELRVSTVW------NDNNPKW------MTRLDFGDVILstggPLRVQVWDQ 485
Cdd:cd04047     4 ELQFSGKKLDKkDFFGKSDPFLEISRQSEDGTWVLVYrtevikNTLNPVWkpftipLQKLCNGDYDR----PIKIEVYDY 79

                          90
                  ....*....|...
gi 2168437580 486 DHGWDDDLLGTCD 498
Cdd:cd04047    80 DSSGKHDLIGEFE 92

C2 domain first repeat present in Tricalbin-like proteins; 5 to 6 copies of the C2 domain are present in Tricalbin, a yeast homolog of Synaptotagmin, which is involved in membrane trafficking and sorting. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the first C2 repeat, C2A, and has a type-II topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2168437580 417 LEVMNFQASGLWGDSF-TKT-DAYLKVFFGGQE--LRVSTVWNDNNPKWMTRLDFgdVILSTGGPLRVQVWDQDHGWDDD 492
Cdd:cd04044     4 LAVTIKSARGLKGSDIiGGTvDPYVTFSISNRRelARTKVKKDTSNPVWNETKYI--LVNSLTEPLNLTVYDFNDKRKDK 81

                          90
                  ....*....|....*
gi 2168437580 493 LLGTCDQNPRSgLHE 507
Cdd:cd04044    82 LIGTAEFDLSS-LLQ 95

C2 domain second repeat present in RasA1 and RasA4; RasA1 and RasA4 are GAP1s (GTPase activating protein 1s ), Ras-specific GAP members, which suppresses Ras function by enhancing the GTPase activity of Ras proteins resulting in the inactive GDP-bound form of Ras. In this way it can control cellular proliferation and differentiation. Both proteins contain two C2 domains, a Ras-GAP domain, a plextrin homology (PH)-like domain, and a Bruton's Tyrosine Kinase (BTK) zinc binding domain. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions. This cd contains the second C2 repeat, C2B, and has a type-I topology.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 2168437580 435 TDAYLKVFFGGQELRVSTVWNDNNPKWMTRLDFgDVILSTGGPLRVQVWDQDHGWDDDLLG 495
Cdd:cd04025    21 SDPFVRVFYNGQTLETSVVKKSCYPRWNEVFEF-ELMEGADSPLSVEVWDWDLVSKNDFLG 80