Homology between the primary structure of α-fetoprotein, deduced from a complete cDNA sequence, and serum albumin

Abstract

The entire DNA complementary to murine .alpha.-fetoprotein mRNA was cloned in the plasmid vector pBR322 and its complete nucleotide sequence determined. The deduced amino acid sequence identifies a hydrophobic prepeptide of 19 amino acids and the complete primary structure of .alpha.-fetoprotein. Its structure reveals extensive homology to serum albumin and suggests that there are 15 disulfide bridges in the .alpha.-fetoprotein molecule, all at the same positions as those found in albumin. The AFP molecule can be organized into a 3-domain structure almost identical to that of serum albumin, suggesting a common ancestral origin of the 2 proteins.