Evidence for coiled‐coil alpha‐helical regions in the long arm of laminin.

Three new laminin fragments, E8, E9 and 25K with mol. wt. 50 000‐280 000, were prepared from a limited elastase digest of laminin and from tissue extracts. They were similar with respect to their rod‐like structure, a high alpha‐helix content, the assembly from two chain segments and immunological cross‐reactivity. Two of the fragments (E8 and E9) possess in addition globular domains which lack alpha‐helices. Chemical, immunological and physical data together with sequence analysis strongly indicate that the alpha‐helical segments are assembled in coiled‐coil structures which are located in the rod of the long arm of laminin. These data give new insights into the overall structure of the protein.