Time-resolved energy transfer measurements of donor-acceptor distance distributions and intramolecular flexibility of a CCHH zinc finger peptide

摘要: Time-resolved frequency-domain fluorescence energy transfer measurements have been used to investigate the solution structure of a single-domain CCHH-type zinc finger peptide. These reveal not only range accessible distances for given donor-acceptor pair within molecule but also degree conformational flexibility that occurs in solution. Two (D-A)-pair peptides synthesized. A single tryptophan residue located at midpoint sequence was donor two different acceptors. One acceptor, attached amino terminus 5-(dimethylamino)- l-naphthalenesulfonyl (DNS) group; second acceptor 7-amino-4-methyl- coumarin-3-acetyl (AMCA) group, €-amino function carboxy-terminal lysine residue. Distance distributions and mutual site-to-site diffusion coefficients were determined these D-A-labeled under zinc-bound, metal-free, denatured conditions. The D-A distance metal-free zinc-bound conditions indicated shorter unique conformation (narrow distribution) when metal bound longer with greater ion absent. No detected zinc- peptide, whereas an appreciable amount measured both Anisotropy on increased all regions peptide chain absence more compact, less flexible bound. It concluded from results metal-bound represents unique, well-defined structure. Comparison there is some residual present