Primary Information
BoMiProt ID	Bomi123
Protein Name	Collectin-43
Organism	Bos taurus
Uniprot ID	P42916
Milk Fraction	Whey
Ref Sequence ID	NP_001002237.1
Aminoacid Length	321
Molecular Weight	33616
FASTA Sequence	Download
Gene Name	CL43
Gene ID	431784
Protein Existence Status	Reviewed: Experimental evidence at protein level
Secondary Information
Protein Function	collagen containing C type lectin; CL-43 is synthesized only in the bovine liver; involved in the innate immune defense; bind to microbial surface carbohydrates inducing aggregation and, thereby, impeding infectivity; binds to the collectin receptor (C1qR) localized on many types of cells identified as a surface variant of calreticulin; show antiviral activities towards influenza A virus and rotaviruses ; displays protective activity against bacterial infections
Biochemical Properties	collectins – family of oligomeric proteins composed of trimeric subunits containing collagen-like sequences joined to C-type lectin domains; presence of collagen- like sequences and globular carbohydrate recognition domains; CL-43 has 1 trimeric unit; trimeric subunits are stabilized by noncovalent interactions (strong hydrophobic forces in α-helical bundle) and covalently by disulfide bridges between cysteine residues in the N-terminal or collagen regions; binds to carbohydrates in the presence of calcium ions; Collectin-43 is found only as a single subunit composed of three identical polypeptide chains; in 2D PAGE CL-43 is seen as two isoforms, with pI (isoelectric point) values of 4.9 and 5.3, corresponding to the native and the truncated form of the molecule; CL-43 binds to a range of sugar residues including mannose, fucose, glucose, maltose, GlcNAc or ManNAc with highest affinity for mannose; binding of carbohydrates involves hydrogen bonds and van der Waal’s interactions, and is stabilized by coordination bonds to the calcium ions
Significance in milk	Antimicrobial proteins - exclusively detected in the colostrum fluid phase
PTMs	CL -43 does not posses N-linked carbohydrate, but it contains hydroxylysine residues in the collagen-like region that are potential O-glycosylation sites
Site(s) of PTM(s) N-glycosylation, O-glycosylation, Phosphorylation
Predicted Disorder Regions	17-150,282-289
DisProt Annotation
TM Helix Prediction	No TM helices
Bibliography	1. Nissen, A., Andersen, P. H., Bendixen, E., Ingvartsen, K. L., and Røntved, C. M. (2017) Colostrum and milk protein rankings and ratios of importance to neonatal calf health using a proteomics approach. J. Dairy Sci. 100, 2711–2728. 2. Lu, J. (1997) Collectins: Collectors of microorganisms for the innate immune system. BioEssays 19, 509–518. 3. Hansen, S., Holm, D., Moeller, V., Vitved, L., Bendixen, C., Reid, K. B. M., Skjoedt, K., and Holmskov, U. (2002) CL-46, a novel collectin highly expressed in bovine thymus and liver. J. Immunol. 169, 5726–5734. 4. Holmskov, U., Laursen, S. B., Malhotra, R., Wiedemann, H., Timpl, R., Stuart, G. R., Tornøe, I., Madsen, P. S., Reid, K. B., and Jensenius, J. C. (1995) Comparative study of the structural and functional properties of a bovine plasma C-type lectin, collectin-43, with other collectins. Biochem. J. 305 ( Pt 3), 889–896. 5. Lim, B. L., Willis, A. C., Reid, K. B., Lu, J., Laursen, S. B., Jensenius, J. C., and Holmskov, U. (1994) Primary structure of bovine collectin-43 (CL-43). Comparison with conglutinin and lung surfactant protein-D. J. Biol. Chem. 269, 11820–11824. 6. Haurum, J. S., Thiel, S., Haagsman, H. P., Laursen, S. B., Larsen, B., and Jensenius, J. C. (1993) Studies on the carbohydrate-binding characteristics of human pulmonary surfactant-associated protein A and comparison with two other collectins: mannan-binding protein and conglutinin. Biochem. J. 293 ( Pt 3), 873–878. 7. Holmskov, U., Teisner, B., Willis, A. C., Reid, K. B., and Jensenius, J. C. (1993) Purification and characterization of a bovine serum lectin (CL-43) with structural homology to conglutinin and SP-D and carbohydrate specificity similar to mannan-binding protein. J. Biol. Chem. 268, 10120–10125. 8. Loveless, R. W., Holmskov, U., and Feizi, T. (1995) Collectin-43 is a serum lectin with a distinct pattern of carbohydrate recognition. Immunology 85, 651–659.