title: Identification and characterization of a chitin-binding protein purified from coelomic fluid of the lugworm Arenicola marina defining a novel protein sequence family.
abstract: We have isolated a novel type of lectin named Arenicola marina lectin-1 (AML-1) from the lugworm A. marina. The lectin was purified from the coelomic fluid by affinity chromatography on a GlcNAc-derivatized column and eluted with GlcNAc. On SDS-PAGE, AML-1 showed an apparent molecular mass of 27 and 31 kDa in the reduced state. The N-terminal amino acid sequences were identical in these two bands. In the unreduced state, a complex band pattern was observed with bands from 35 kDa to more than 200 kDa. Two different full-length clones encoding polypeptides of 241 and 243 amino acids, respectively, were isolated from a coelomocyte cDNA library. The two clones, designated AML-1a and AML-1b, were 92% identical at the protein level and represent a novel type of protein sequence family. Purified AML-1 induced agglutination of rabbit erythrocytes, which could be inhibited by N-acetylated saccharides. Recombinant AML-1b showed the same band pattern as the native protein, whereas recombinant AML-1a in the reduced state lacked a 27 kDa band. AML-1b bound GlcNAc-derivatized columns and chitin, whereas AML-1a did not bind to these matrices. Immunohistochemical analysis revealed that AML-1 is expressed by coelomocytes in the nephridium and in round cells in the epidermis and in eggs. Moreover, AML-1 expression was up-regulated in response to a parasitic infection. We conclude that AML-1 purified from coelomic fluid is encoded by AML-1b and represents a novel type of protein family that binds acetylated components.
authors.affiliation: Department of Cardiovascular and Renal Research, University of Southern Denmark, J.P. Winsloews Vej 25.3, 5000 Odense C, Odense, Denmark.
authors.forename: Nina
authors.initials: N
authors.lastname: Vitashenkova
authors.forename: Jesper Bonnet
authors.initials: JB
authors.lastname: Moeller
authors.forename: Rikke
authors.initials: R
authors.lastname: Leth-Larsen
authors.forename: Anders
authors.initials: A
authors.lastname: Schlosser
authors.forename: Kit Peiter
authors.initials: KP
authors.lastname: Lund
authors.forename: Ida
authors.initials: I
authors.lastname: Tornøe
authors.forename: Lars
authors.initials: L
authors.lastname: Vitved
authors.forename: Søren
authors.initials: S
authors.lastname: Hansen
authors.forename: Anthony
authors.initials: A
authors.lastname: Willis
authors.forename: Alexandra D
authors.initials: AD
authors.lastname: Kharazova
authors.forename: Karsten
authors.initials: K
authors.lastname: Skjødt
authors.forename: Grith Lykke
authors.initials: GL
authors.lastname: Sorensen
authors.forename: Uffe
authors.initials: U
authors.lastname: Holmskov
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001826:Body Fluids / Q000378:metabolism*; D016466:CHO Cells; D002686:Chitin / Q000378:metabolism*; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000378:metabolism; D005944:Glucosamine / Q000378:metabolism; D015801:Helminth Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D006376:Helminths / Q000378:metabolism*; D006385:Hemagglutination Inhibition Tests; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D015801:Helminth Proteins; D010455:Peptides; D011994:Recombinant Proteins; D002686:Chitin; D005944:Glucosamine