Open AccessCharacterization of the Trimeric, Self‐Recognizing Geodia cydonium Lectin I
Author(s) -
MÜLLER Werner E. G.,
CONRAD Jürgen,
SCHRÖDER Christina,
ZAHN Rudolf K.,
KURELEC Branko,
DREESBACH Karin,
UHLENBRUCK Gerd
Publication year - 1983
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1983.tb07457.x
Subject(s) - lectin , biology , zoology , evolutionary biology , microbiology and biotechnology
A d ‐galactose‐specific lectin I was extracted from the sponge Geodia cydonium and purified by affinity chromatography. The molecular weight of lectin I as determined by high‐pressure liquid gel chromatography, was found to be 36500 ± 1300. Disc gel electrophoresis in the presence and in the absence of sodium dodecyl sulfate showed that lectin I is a trimer composed of three different subunits ( M r : 13800, 13000 and 12200); two of the three subunits are linked by one disulfide bond. Isoelectric focusing gave a pI of 5.6 for the native molecule and a pI of 4.4 and of 7.4 for the subunits. The three subunits carry carbohydrate side chains, composed of d ‐galactose (94%) and of arabinose (5%). Based on experiments with lectins, the terminal d ‐galactose residues are bound by β1→6 and/or β1→4 glycosidic linkages. The Geodia lectin I contains, besides two carbohydrate recognition sites, at least one receptor site for a second lectin I molecule.