Recognition of acetylated oligosaccharides by human L-ficolin

The complement system is a protein cascade capable of neutralizing invading pathogens. One of its activation pathways is the lectin pathway which is dependent on the binding of MBL or the ficolins. The specificity of L-ficolin binding has been investigated previously and it was observed that binding is dependent on acetyl groups. If this was the only requirement this would enable L-ficolin to bind to most mammalian glycosylations since they contain acetylated monosaccharides. To investigate this further L-ficolin was subjected to glycan-array analysis in which L-ficolin binding to 279 different glycans was investigated. Few of these bound L-ficolin above background level but clear structural requirements were discovered.