Complete primary structure of the α1‐chain of human basement membrane (type IV) collagen

Abstract
We have determined the primary structure of the α1(IV)‐chain of human type IV collagen by nucleotide sequencing of overlapping cDNA clones that were isolated from a human placental cDNA library. The present data provide the sequence of 295 amino acids not previously determined. Altogether, the α1(IV)‐chain contains 1642 amino acids and has a molecular mass of 157625 Da. There are 1413 residues in the collagenous domain and 229 amino acids in the carboxy‐terminal globular domain. The human α1(IV)‐chain contains a total of 21 interruptions in the collagenous Gly‐X‐Y repeat sequence. These interruptions vary in length between two and eleven residues. The α1(IV)‐chain contains four cysteine residues in the triple‐helical domain, four cysteines in the 15‐residue long noncollagenous sequence at the amino‐terminus and 12 cysteines in the carboxy‐terminal NC‐domain