Ultrastructure of the Human Complement Component, Clq

Abstract

The human complement component, Clq, is a fragile molecule of delicate structure consisting of three distinct parts, a central subunit, connecting strands, and terminal subunits. Each terminal subunit is further subdivided into a large and a small subunit, and the central subunit appears to be divided into two equal parts. In the intact molecule, six connecting strands link six terminal subunits by their larger subdivision to the central subunit. The overall diameter of the molecule when viewed from the "top" is about 35 nm (350 A).