Test
Collagen type IV is a type of collagen found primarily in the basal lamina. The type IV collagen C4 domain at the C-terminus is not removed in post-translational processing and the fibers link head-to-head rather than in parallel. Also collagen type IV lacks the regular glycine in every third residue necessary for the tight collagen helix. This makes the overall arrangement more sloppy with kinks. These two features cause collagen IV to form in a sheet the form of the basal lamina. There are six human genes associated with collagen IV: COL4A1 COL4A2 COL4A3 COL4A4 COL4A5 and COL4A6.