Delivery of external proteins into the cytoplasm using protein capsules modified with IgG on the surface, created from the amphiphilic two helix-bundle protein OLE-ZIP.

This study explores a new method for delivering therapeutic proteins into specific cells using OLE-ZIP capsules that present IgG. OLE-ZIP capsules is a spherical caspules prepared from amphihilic dimetic coiled-coil peptide, OLE-ZIP. Upon presenting cetuximab, these capsules showed preferential uptake in A431 cells and increased cytotoxicity when loaded with RNase A.

Control of Helical Chirality of Ferrocene-Dipeptide Conjugates by the Secondary Structure of Dipeptide Chains.

Controlling helical chirality and creating protein secondary structures in cyclic/acyclic ferrocene-dipeptide bioorganometallic conjugates were achieved by adjusting the conformational flexibility of the dipeptide chains. In systems reported to date, the helical chirality of a conjugate was determined by the absolute configuration of the adjacent amino acid reside. In contrast, it was possible to induce both M- and P-helical chirality, even when the configuration of the adjacent amino acid was the same. It is particularly interesting to note that M-helical chirality was produced in a cyclic ferrocene-dipeptide conjugate composed of the l-Ala-d-Pro-cystamine-d-Pro-l-Ala dipeptide sequence (1), in which a type II ß-turn-like secondary structure was established.

Controlled self-assembling structures of ferrocene-dipeptide conjugates composed of Ala-Pro-NHCH2CH2SH chain.

Bioorganometallic ferrocene-dipeptide conjugates with the Ala-Pro-cysteamine chain, Fc-L-Ala-L-Pro-NHCH2CH2SH (2) and Fc-L-Ala-D-Pro-NHCH2CH2SH (4) (Fc=ferrocenoyl), were prepared by the reduction of the ferrocene-dipeptide conjugates, Fc-L-Ala-L-Pro-cystamine-L-Pro-L-Ala-Fc (1) or Fc-L-Ala-D-Pro-cystamine-D-Pro-L-Ala-Fc (3), respectively. Control of the self-assembling structures of the ferrocene-dipeptide conjugates was demonstrated by changing the chirality of the amino acid. The molecular structure of 2 composed of the L-Ala-L-Pro-NHCH2CH2SH chain confirmed the formation of intramolecular hydrogen bond of N-H⋯N pattern between the NH of cysteamine moiety and the nitrogen of Pro moiety. Furthermore, intermolecular hydrogen bonds between NH (Ala) and CO (Pro of another molecule) and between NH (cysteamine) and CO (the ferrocenoyl moiety of another molecule) were formed, wherein each molecule is connected to four neighboring molecules by continuous intermolecular hydrogen bonds to form the hydrogen-bonded molecular assembling structure. On the contrary, the left-handed helical assembly through an intermolecular hydrogen-bonding network of 15-membered intermolecularly hydrogen-bonded ring between NH (Ala) and CO (the ferrocenoyl moiety of another molecule) and between NH (the cysteamine moiety of another molecule) and CO (Ala) was observed in the crystal packing of 4 composed of the L-Ala-D-Pro-NHCH2CH2SH chain.