Galactose binding lectin domain;

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gi 1972252400  51 LSCPAGKVISIVLGNYGRFSVAVCLPDNdivpSNINCQNHKTKSILEKN 99
Cdd:pfam02140   1 LSCPPGKVISILFASYGRPDGTTCPSFI----QGTNCHSPNSLAIVSKA 45

galactose/rhamnose binding lectin domain found in Toxopneustes pileolus rhamnose-binding lectin SUL-I and similar proteins; SUL-I is a galactose/rhamnose-binding lectin with mitogenic, chemotactic, and cytotoxic activity. These activities can be triggered by binding of the lectin to specific carbohydrate chains on target cells. SUL-I may be involved in self-defense against invading microorganisms. SUL-I is composed of three distinctive domains with a folding structure similar to galactose/rhamnose-binding lectin domain found in proteins such as mammalian latrophilins, Oncorhynchus keta L-rhamnose-binding lectins (CSLs), and Silurus asotus rhamnose-binding lectin (SAL). The family also includes Heliocidaris crassispina D-galactoside-specific lectin, also known as sea urchin egg lectin or SUEL, and Echinometra lucunter L-rhamnose-binding lectin ELEL-1, both of which contain only one galactose/rhamnose-binding lectin domain. SUEL binds D-galactoside. It may play an important role in the activation of eggs triggered by fertilization, or in their subsequent differentiation. The dimeric form is essential for hemagglutination activity of SUEL. ELEL-1 is a rhamnose-binding lectin that also binds alpha-D-melibiose, alpha-D-lactose, beta-D-lactose, methyl-alpha-D-galactopyranoside, methyl-beta-D--galactopyranoside and D-galactose, but not D-arabinose, L-fucose, D-glucose, D-mannose, D-maltose, D-sucrose, N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, N-acetyl-D-mannosamine-D-xylose, or by glycoproteins orosomucoid, thyroglobulin, ovomucoid and porcine stomach mucin. It shows cation-independent hemagglutinating activity against rabbit and human erythrocytes. ELEL-1 agglutinates cells of Gram-positive bacterial species S. aureus but not those of Gram-negative E. coli.

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gi 1972252400  42 TICDGEAAELSCPAGKVISIVLGNYGRFSVAVClPDNDIvpSNINCQNHKTKSILEK 98
Cdd:cd22827     2 RVCEGQTLTISCPAGKVIDIVSANYGRTDSSTC-PSGGI--KNTNCRASNSLSIVRN 55

Galactose/rhamnose-binding lectin domain; Galactose/rhamnose-binding lectin domain is formed from a four-stranded antiparallel beta-sheet which packs against an alpha-helix. It was originally described as galactose-binding lectin domain since it was found in a galactose-binding sea urchin egg lectin (SUEL). SUEL was first isolated as a D-galactoside binding lectin, it was later shown that it binds to L-rhamnose preferentially. Galactose/rhamnose-binding lectin domain is also found in many rhamnose-binding lectins, such as Oncorhynchus keta L-rhamnose-binding lectins (CSLs) and Silurus asotus rhamnose-binding lectin (SAL). In addition, the superfamily includes many SUEL/CSLs/SAL homologous proteins, such as plant beta-galactosidases, mammalian latrophilins, Caenorhabditis elegans protein EVA-1 and its homolog, human protein EVA-1 homolog C (also known as C21orf63). Due to the lack of galactose/rhamnose-binding key residues, some superfamily members may not form a binding pocket for galactose/rhamnose. Therefore, they are unlikely to act as galactose/rhamnose-binding lectins.

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gi 1972252400  42 TICDGEAAELSCPAGKVISIVLGNYGRFSVAVCLPDNDIVPSNINCQNHKTKSILEK 98
Cdd:cd22823     2 TACEGETLTLSCPSGQVIKILSAFYGRTDGTTCCCGPNNTSDTNCCSPDVLDIVKEL 58

first galactose/rhamnose binding lectin domain found in Caenorhabditis elegans protein EVA-1, human protein EVA-1 homolog C and similar proteins; The family includes Caenorhabditis elegans protein EVA-1 and its homologs, such as human protein EVA-1 homolog C (also known as C21orf63). EVA-1 functions as an UNC-40 coreceptor to enhance attraction to the MADD-4 guidance cue in C. elegans. It also acts as a receptor for slt-1 and is required for the guidance of the AVM pioneer axon to the ventral nerve cord. Human C21orf63 is a type-1 transmembrane heparin-binding protein. Both human C21orf63 is a type-1 transmembrane heparin-binding protein. Members in this family contain two tandem galactose/rhamnose-binding lectin domains. This model corresponds to the first one.

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gi 1972252400  44 CDGEAAELSCPAGKVISIVLGNYGR 68
Cdd:cd22828     8 CDGEELTLRCPPNTTISIQSAFYGR 32

galactose/rhamnose binding lectin domain found in latrophilins; Latrophilins, also called lectomedins or latrotoxin receptors, belong to Group I adhesion GPCRs, which also include ETL (EGF-TM7-latrophilin-related protein). These receptors are a member of the adhesion family (subclass B2) that belongs to the class B GPCRs. Three subtypes of latrophilins have been identified: latrophilin-1 (LPHN1), Latrophilin-2 (LPHN2), and Latrophilin-3 (LPHN3). The LPHN1 is a brain-specific calcium-independent receptor of alpha-latrotoxin, a potent presynaptic neurotoxin from the venom of the black widow spider that induces massive neurotransmitter release from sensory and motor neurons as well as endocrine cells, leading to nerve-terminal degeneration. LPHN2 and LPHN3, although sharing strong sequence homology to LPHN1, do not bind alpha-latrotoxin. While LPHN3 is also brain specific, LPHN2, is ubiquitously distributed. The endogenous ligands for these two receptors are unknown. All members in this family contain a galactose/rhamnose-binding lectin domain at N-terminus.

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gi 1972252400  44 CDGEAAELSCPAGKVISIVLGNYGRFSVAVCLPDNDIvpSNINCQNHKTKSILEK 98
Cdd:cd22826     6 CEGYKIRLRCPGSDVIMIESANYGRTDSSTCPSDPNM--TDTNCYLPDALAIVSQ 58

galactose/rhamnose binding lectin domain found in Hydra vulgaris nematogalectin and similar proteins; Nematogalectin, also called nemgal, is a nematocyst protein with an N-terminal GlyXY domain and a galactose/rhamnose binding lectin domain. There are two nematogalectins, A and B, in Hydra, and they are the products of alternative splicing. They are major components of the nematocyst tubule. Nematogalectin functions as a trimer that could bind to multiple chondroitin glycosaminoglycan molecules and stabilize the chondroitin proteoglycan layer.

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gi 1972252400  43 ICDGEAAELSCPAGKVISIVLGNYGRFSVAVCLPDNDIVPSNINCqNHKTKSILEK 98
Cdd:cd22838     6 ACEGEKLWLQCPQYELIKIKSAFWGRDDKKTCPHPPPGLPSNKMC-ETDEENVKKK 60