This domain is a novel carbohydrate-binding domain found on micronemal proteins. Micronemal proteins (MICs) are released onto the parasite surface just before invasion of host cells and play important roles in host cell recognition, attachment and penetration. Toxoplasma gondii can infect and replicate within all nucleated cells [1]. This domain interacts with sialylated oligosaccharides; the protein in Toxoplasma gondii is a monomer but several MAR domains are carried on the protein. Each MAR domain contains one central sialic acid-binding pocket [2].

1: Atomic resolution insight into host cell recognition by Toxoplasma gondii. Blumenschein TM, Friedrich N, Childs RA, Saouros S, Carpenter EP, Campanero-Rhodes MA, Simpson P, Chai W, Koutroukides T, Blackman MJ, Feizi T, Soldati-Favre D, Matthews S; EMBO J. 2007;26:2808-2820. PMID:17491595

2: MARveling at parasite invasion. Hager KM, Carruthers VB; Trends Parasitol. 2008;24:51-54. PMID:18203663