Rh. Lorentsen et al., The heparin-binding site in tetranectin is located in the N-terminal region and binding does not involve the carbohydrate recognition domain, BIOCHEM J, 347, 2000, pp. 83-87
Tetranectin is a homotrimeric plasma and extracellular-matrix protein that
binds plasminogen and complex sulphated polysaccharides including heparin.
In terms of primary and tertiary structure, tetranectin is related to the c
ollectin family of Ca2+ binding C-type lectins. Tetranectin is encoded in t
hree exons. Exon 3 encodes the carbohydrate recognition domain, which binds
to kringle 4 in plasminogen at low levels of Ca2+. Exon 2 encodes an a-hel
ix, which is necessary and sufficient to govern the trimerization of tetran
ectin by assembling into a triple-helical coiled-coil structural element. H
ere we show that the heparin-binding site in tetranectin resides not in the
carbohydrate recognition domain but within the N-terminal region, comprisi
ng the 16 amino acid residues encoded by exon 1. In particular, the lysine
residues in the decapeptide segment KPKKIVNAKK (tetranectin residues 6-15)
are shown to be of primary importance in heparin binding.