11.   There have been sporadic assertions in the past of finding very ancient protein fragments in fossils, and more frequent claims of ancient DNA from specimens preserved in amber.

12.   They could recognize protein fragments but not kill the cells.

13.   When researchers looked in protein databases, trying to match viral protein fragments with self-protein fragments, their amino acids did not always line up exactly.

14.   Without the drug, the protein fragments would float helplessly in the cell.

15.   Many point to overproduction of natural protein fragments called amyloid-beta, which form clumps in the brains of patients.

16.   The poison targets an HIV protein fragment on the surface of such cells.

17.   The poison homed in on a protein fragment found on the surface of the tumor cells.