A short peptide derived from the antisense homology box of Fas ligand induces apoptosis in anti-Fas antibody-insensitive human ovarian cancer cells

Role of complementary proteins in autoimmunity: an old idea re-emerges with new twists

It has been suggested that complementary proteins are involved in autoimmunity through a network involving idiotype-anti-idiotype reactions termed 'autoantigen complementarity'. We propose that complementary proteins, which occur naturally or result from cellular dysfunction, might be more common than recognized currently. This implies that the role of complementary proteins in autoimmunity merits increasing investigation. The concept of complementary proteins is reviewed here and, also, new ideas are presented that underscore the role of open-reading frames in frame -1 of recognized genes in the production of complementary proteins (frame -1 is the reverse complement sequence of a gene that uses the antisense of the codons of frame +1). Furthermore, a novel role for palindromic sequences in autoimmunity and a new model explaining how abzymes and autoantigen complementarity might be related are proposed.

Structure-based design of an agonistic peptide targeting Fas

A small agonistic peptide FRAP-4 (WEWT, Fas reactive peptide-4) that binds to the human Fas molecule was discovered using our computer screening strategy named the Amino acid Complement Wave (ACW) method, which is based on the complementarities of interacting amino acids between comprehensive testing peptides and a target protein surface pocket. In silico docking studies demonstrated the specific interaction of FRAP-4 with the main Fas ligand (FasL) binding domain in the Fas molecule. An octamer of this peptide produced by carboxyl terminal linkages of polylysine branches (MAP), (FRAP-4)8-MAP, effectively induced apoptosis in human ovarian cancer cell line NOS4 cells that was associated with the activation of caspases-8, -9 and -3, and the cleavage of PARP. Alanine substitution of the N-terminal W in FRAP-4 resulted in complete loss of FasL-mimetic action of (FRAP-4)8-MAP, suggesting that the aromatic functionality at the N-terminal position W appears to play an essentially important role in Fas binding ability. These observations indicate that the FasL-mimetic peptide should serve as an excellent starting point for the design of effective compounds with FasL-mimetic activity. Furthermore, the ACW method for the structure-based design of optimized small peptides against receptor molecules such as Fas could open new avenues for the development of peptide mimetic and nonpeptidic organic forms to generate novel effective pharmaceuticals.

Genomic drug discovery for apoptosis regulation using a new computer screening amino acid complement wave method

A novel caspase-3-specific inhibitory peptide and an agonistic peptide that binds to the Fas molecule were discovered using our computer screening strategy called the amino acid complement wave (ACW) method, which is based on the complementarities of interacting amino acids between comprehensive testing peptides and a target protein surface pocket. The precise binding configurations of the designed peptides on the three-dimensional (3D) structure of the target protein and the prediction of binding affinities (DeltaG) are determined by the molecular docking program. A designed novel tetrapeptide inhibitor of caspase-3, Ac-DNLD-CHO, was revealed to have potent and specific inhibitory activity. When a designed Fas ligand mimic peptide (Fas reactive peptide-4, FRAP-4) was multimerized by carboxyl terminal linkages of polylysine branches (MAP), the octamer (FRAP-4)(8)-MAP effectively induced apoptosis of human ovarian cancer cell line NOS4 cells. Thus the ACW method for structure-based design of optimized small peptides can be used to further develop small peptidomimetic and nonpeptidic organic forms into a new generation of effective pharmaceuticals.