| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
I have utilized sequential information from an anti-heme monoclonal antibody to develop the novel porphyrin-binding peptides. Several peptides which have an intramolecular disulfide bond in different position and different chain length were prepared. The affinities of peptides for meso-tetrakis (4-carboxyphenyl) porphyrin were increased by an appropriate conformational restraint using a disulfide bond. Detail studies using a representative 12-peptide, 12C4, whose length was reduced from 20-residues of the CDR, indicated that both the hydrophobic and electrostatic interactions were essential factors in the peptide-porphyrin interaction. Moreover, the two-dimensional 1H-NMR spectroscopy revealed the conformational feature of the peptide and the critical residues for the porphyrin-binding. According to the obtained results, a further minimized 9-peptide, 9L, was successfully re-designed with a sequence capable of forming a β-turn instead of a disulfide bond. Furthermore, affinity maturation studies of 9L were performed using a combinatorial approach such as the spot-synthesis method. Systematic amino acid replacements using this method made possible to obtain the peptides which have an improved affinity for porphyrins. Thus, the designing approach of peptides targeted to porphyrins was demonstrated by the combination of the antibody information and the rationally-designed combinatorial method. Using the same strategy, IgE binding peptides were also constructed, and the effective binding with IgE was demonstrated.
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