Mannan-binding lectin Mannan-binding lectin Mannose-binding lectin (MBL), also called mannose-binding protein or mannan-binding protein (MBP), is a lectin that is instrumental in innate immunity via the lectin pathway. MBL has an oligomeric structure (400-700 kDa), built of subunits that contain three presumably identical peptide chains of about 30 kDa each. Although MBL can form several oligomeric forms, there are indications that dimers and trimers are not biologically active and at least a tetramer form is needed for activation of complement. Human MBL2 gene is located on chromosome 10q11.2-q21. Mice have two homologous genes, but in human the first of them was lost.
Alpha-keratin of most biological importance of alpha-keratin is its structural stability. When exposed to mechanical stress, α-keratin structures can retain their shape and therefore can protect what they surround. Under high tension, alpha-keratin can even change into beta-keratin, a stronger keratin formation that has a secondary structure of beta-pleated sheets. Alpha-keratin tissues also show signs of viscoelasticity, allowing them to both be able to stretch and absorb impact to a degree, though they are not impervious to fracture. Alpha-keratin strength is also affected by water content in the intermediate filament matrix; higher water content decreases the strength and stiffness of the