Type IV (tIV) collagen forms the supportive scaffold of most basement membranes. A property of this glycoprotein is the ability to polymerize by binding to adjacent tIV molecules in a specific manner. Most functional studies, including reports from our group, have focused on tIV derived from the EHS tumor which is the only basement membrane collagen that can be extracted intact and in high yields. This particular form of tIV has the composition: (α1)2(α2). Recently, novel chains have been reported in the glomerular and other basement membranes. Protein components of the NCI domain of an α3(IV), α4(IV) and the cDeoxyribonucleic AcidDeoxyribonucleic Acid (DNA)a molecule that carries most of the genetic instructions used in the development, functioning and reproduction of all known living organisms and many viruses. DNA (along with RNA) is a nucleic acid; alongside proteins and carbohydrates, nucleic acids compose the three major macromolecules essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix. The two DNA strands are known as polynucleotides since they are composed of simpler units called nucleotides.[2] Each nucleotide is composed of a nitrogen-containing nucleobase^aEUR"either cytosine (C), guanine (G), adenine (A), or thymine (T)^aEUR"as well as a monosaccharide sugar called deoxyribose and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. of an α3NCI with EHS-tIV and compare them with interactions between whole, b-GBM-NCI and α1NC1 to EHS-tIV.