Dynamic Aspects of the Immunoglobulin Structure

ABSTRACT

Immunoglobulin (Ig) molecules are composed of Fab and Fc portions tethered by a hinge region that enables them to rotate and flex, relative to each other. Variable (V) and constant (C) domains of the Fab are connected by a flexible elbow region that is responsible for the movements of the V and C heterodimers. Significant movements of Fc domains have also been documented. The Ig portion’s rotational freedom greatly enhances its ability to react with antigens and cell receptors, often simultaneously. The antigen-combining site also displays a dynamic structure. The ability of its various parts to change position greatly facilitates their complexation with various antigenic compounds.

KEYWORDS:

• Immunoglobulin flexibility
• Fab elbow angle
• mobility of Fab and Fc domains
• intrinsic domain flexibility
• combining site flexibility
• glycan residue movements