The design and synthesis of glycol-functionalized porphyrins that contain one to four low molecular weight glycol chains that are linked via ether bonds to the meta-phenyl positions of meso-tetraphenylporphyrin and the comparison of fluorinated and nonfluorinated para derivatives are reported. The cellular uptake and photodynamic activity significantly depend on terminal groups of the glycol substituent. Hydroxy glycol porphyrins, in contrast with methoxy glycol porphyrins, show efficient intracellular transport and a high induction of apoptosis in tumor cell lines in vitro . Furthermore, the ethylene glycol chain at the meta position exhibits a superior efficacy that leads to the permanent ablation of human breast carcinoma (MDA-MB-231) in nude mice. In addition, fluorination enhanced the photosensitizing potential of para-phenyl derivatives. The analysis of the cell-death mechanism revealed that glycol-functionalized porphyrins represent novel nonmitochondrially localized photosensitizers that have a profound ability to induce apoptosis in tumor cells that act upstream of caspase activation. The strong interaction with a tumor marker (sialic acid) indicates the preferential association of these compounds with tumor cells.

Eight meso-aryl calixphyrin derivatives were synthesized and their conformational equilibria and transitions studied with temperature-dependent NMR spectroscopy. On the basis of density functional computations, several conformer species could be identified and observed changes in chemical shifts explained. In some compounds, the aryl group rotation and porphyrin ring flipping could be monitored independently, as their NMR coalescence temperatures were well-separated. Calculated relative conformer energies, transition barriers, and isotropic shieldings agree well with the experimental data. In the meso-substituted porhyrins (calixphyrins) the sp3 carbon atoms perturb their pi-electron system and significantly modify the molecular shape and the flexibility. Even when the conjugation of the pi-electron system was destroyed by the nonplanarity, far-range electronic induction effects still exist and influence chemical shielding and molecular geometry. The aryl functional groups moderately modify the structure of the calixphyrin ring and thus can be used for fine-tuning of the mechanical and chemical properties of these compounds.

Tetraphenylporphyrin conjugates with one (PB1) and four (PB4) cobalt(III) bis(1,2-dicarbollide) substituents were synthesized and the physicochemical and photophysical properties as well as inhibition of HIV-1 protease were described. In methanol, both PB1 and PB4 were monomeric producing the triplet states and singlet oxygen after excitation. The triplet states of PB4 were quickly protonated. Porphyrins exhibited a small decrease of the quantum yields of the singlet oxygen formation (17% for PB4 and 13% for PB1) as compared with 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin. On the contrary, no singlet oxygen was detected in aqueous solutions because of strong aggregation. Light scattering and atomic force microscopy (AFM) measurements documented that the behavior of aggregates in aqueous solutions is fairly complex and depends on pH, concentration, and aging. The aggregation started from spherical particles in neutral solutions. In acidic solutions, extended aggregation occurred because of slow protonation of the porphyrin pyrrole nitrogen atoms. Both PB1 and PB4 are new representatives of nonpeptide HIV-1 protease inhibitors. Their activity increased with the increasing number of the cobalt(III) bis(1,2-dicarbollide) substituents and was characterized with the IC50 values of 290+/-44 nM for PB1 and 77+/-13 nM for PB4.

Specific antibodies interfere with the function of human tumor-associated carbonic anhydrase IX (CA IX), and show potential as tools for anticancer interventions. In this work, a correlation between structural elements and thermodynamic parameters of the association of antibody fragment Fab M75 to a peptide corresponding to its epitope in the proteoglycan-like domain of CA IX, is presented. Comparisons of the crystal structures of free Fab M75 and its complex with the epitope peptide reveal major readjustments of CDR-H1 and CDR-H3. In contrast, the overall conformations and positions of CDR-H2 and CDR-L2 remain unaltered, and their positively charged residues may thus present a fixed frame for epitope recognition. Adoption of the altered CDR-H3 conformation in the structure of the complex is accompanied by an apparent local stabilization. Analysis of domain mobility with translation-libration-screw (TLS) method shows that librations of the entire heavy chain variable domain (V(H)) decrease and reorient in the complex, which correlates well with participation of the heavy chain in ligand binding. Isothermal titration microcalorimetry (ITC) experiments revealed a highly unfavorable entropy term, which can be attributed mainly to the decrease in the degrees of freedom of the system, the loss of conformational freedom of peptide and partially to a local stabilization of CDR-H3. Moreover, it was observed that one proton is transferred from the environment to the protein-ligand complex upon binding. Molecular dynamics simulations followed by molecular mechanics/generalized Born surface area (MM-GBSA) calculations of the ligand (epitope peptide) binding energy yielded energy values that were in agreement with the ITC measurements and indicated that the charged residues play crucial role in the epitope binding. Theoretical arguments presented in this work indicate that two adjacent arginine residues (ArgH50 and ArgH52) are responsible for the observed proton transfer.