Snaclec family (C-type lectin-like protein)
Common C-type lectins are non-enzymatic proteins that bind carbohydrate in a calcium-dependent manner. They are found extensively throughout plant and animal species, including venom secretions. In
, lectins are classified into
true C-type lectins (CTLs)
and snaclecs (also known as C-type lectin-like proteins or CLPs) that lack the carbohydrate-binding loop present in true C-type lectins and consequently do not bind sugars (
). Based on their biological activity, they can be divided into four subgroups:
1. anticoagulant proteins that specifically bind to coagulation factors IX (F9), X (F10) or thrombin/prothrombin (F2).
2. coagulant metalloproteinase-lectin complex that binds to prothrombin (F2) or coagulation factor X (F10).
3. platelet aggregation agonists, which affect platelet aggregation by binding to GPIb, either alone or in complex with von Willebrand factor (vWF), integrin alpha-2/beta-1 (ITGA2/ITGB1), platelet glycoprotein VI (GP6) and lectin CLEC-2 (CLEC1B).
4. platelet aggregation antagonists, which affect platelet aggregation by binding to GPIb in complex with vWF, and integrin alpha-2/beta-1 (ITGA2/ITGB1).
Snaclecs are mostly heterodimers of alpha (14-15 kDa) and beta (13-14 kDa) subunits, nearly always linked covalently via a disulfide bond. Some heterotetramers have also been described (
). The heterodimers are often further multimerized either non-covalently, or covalently via additional disulfide bonds, to form larger structures. Under physiological conditions many snaclecs can form non-covalent higher order multimers that are much more effective in clustering receptors and activating platelets than the simple covalent multimers might suggest.
has been given to C-type lectin-like proteins (CLPs) and means SNAke C-type LECtinS. It was given by
Clemetson et al., 2009
to avoid confusion with classic C-type lectins and to convey information about the hetero- or oligomeric structure.
Related protein family
True venom lectin family
Hemostasis impairing toxin
Blood coagulation cascade activating toxin
Blood coagulation cascade inhibiting toxin
Platelet agg. activating toxin
Platelet agg. inhibiting toxin
This protein family in
Ogawa et al., 2005
Zelensky and Gready, 2005
SIB Swiss Institute of Bioinformatics