Lectin pathway Lectin pathway The lectin pathway is a type of cascade reaction in the complement system, similar in structure to the classical complement pathway, in that, after activation, it proceeds through the action of C4 and C2 to produce activated complement proteins further down the cascade. In contrast to the classical complement pathway, the lectin pathway does not recognize an antibody bound to its target. The lectin pathway starts with mannose-binding lectin (MBL) or ficolin binding to certain sugars. In this pathway, mannose-binding lectin binds to mannose, glucose, or other sugars with 3- and 4-OH groups placed in the equatorial plane,
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