Domain IV, consisting of about 230 residues, represents a particular protein module so far found only in lamininb1 andb2 chains. Both domains were obtained by recombi-nant production in mammalian cells. They showed a globular structure, as expected from electron microscopic examination of laminins. Fragmentb1IV was obtained as a monomer and a disul®de-bonded dimer, and both were modi®ed to 50% by a single chondroitin sulfate chain attached to Ser721 of an SGD consensus sequence.
