THE N-TERMINAL GLOBULAR DOMAIN OF THE LAMININ ALPHA-1 CHAIN BINDS TO ALPHA-1-BETA-1 AND ALPHA-2-BETA-1 INTEGRINS AND TO THE HEPARAN SULFATE-CONTAINING DOMAINS OF PERLECAN

The N-terminal domains VI plus V (62 kDa) and V alone (43 kDa) of the laminin alpha 1 chain were obtained as recombinant products and shown to be folded into a native form by electron microscopy and immunologic al assays. Domain VI alone, which corresponds to an LN module, did not represent an autonomously folding unit in mammalian cells, however. F ragment alpha 1VI/V, but not fragment alpha 1V, bound to purified alph a 1 beta 1 and alpha 2 beta 1 integrins, to heparin, and to heparan su lfate-substituted domains I acid V of perlecan, This localized the bin ding activities to the LN module, which contains two basic sequences s uitable for heparin interactions. (C) 1998 Federation of European Bioc hemical Societies.