Exoskeletal proteins from the crab, Cancer pagurus

Twelve proteins from calcified regions and five from flexible regions (arth rodial membranes) of the exoskeleton of Cancer pagurus have been purified a nd sequenced. One of the proteins from calcified exoskeleton is identical t o one of the arthrodial membrane proteins. Several of the proteins from the calcified regions resemble proteins from corresponding regions of the exos keleton of the lobster, Homarus americanus, in containing either two or fou r copies of an 18-residue sequence motif, which so far has been found only in crustacean calcified exoskeletons. The proteins obtained from the flexib le arthrodial membranes resemble the proteins from lobster arthrodial membr anes, and the similarities are shared with a number of proteins from flexib le cuticles in insects, indicating that the common features in these protei ns may be important for the mechanical properties of the materials in which they occur. (C) 1999 Elsevier Science Inc. All rights reserved.