Use of the metal replica technique in the electron microscopy of collagen

The authors present a survey of visualization of the individual types of collagen by the metal replica technique, special attention was paid to the visualization of type IX collagen, which, together with type XI, is a minor component of cartilage collagen. The molecule of this collagen type contains three collagen and four non-collagen domains and during the isolation involving pepsin digestion it is cleaved into MHW and LMW fragments. The HMW fragment can be further cleaved into shorter and longer arm. Results of statistical evaluation of 199 measured molecular fragments showed the following length: whole molecule 194 +/- 23 nm, HMW 136 +/- 16 nm, the longer arm of the HMW 87 +/- +/- 12 nm and the LMW of shorter arm of the HMW 43 +/- 9 nm.