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Peter Hinterdorfer

Publications and source records attributed to Peter Hinterdorfer.

7 recordsLinked to original sources
PubMed2025

Plant-derived recombinant macromolecular PAP-IgG Fc as a novel prostate cancer vaccine candidate eliciting robust immune responses.

Prostatic acid phosphatase (PAP) is a specific protein that is highly expressed in prostate cancer. In this study, we constructed two recombinant PAP fusion genes: PAP fused to the immunoglobulin G (IgG) Fc fragment (designated PAP-Fc) and PAP-Fc fused to the endoplasmic reticulum retention sequence KDEL (designated PAP-FcK). Transgenic Nicotiana tabacum plants expressing these recombinant macromolecular proteins (MPs) were generated using Agrobacterium-mediated transformation, and the presence of both genes was confirmed through genomic PCR. Western blot analysis validated the expression of PAP-Fc and PAP-FcK MPs, which were successfully purified via protein A affinity chromatography. Size-exclusion high-performance liquid chromatography revealed dimeric peaks for PAP-Fc (PAP-FcP) and PAP-FcK (PAP-FcKP). Bio-transmission electron microscopy demonstrated 'Y'-shaped protein particles resembling antibody structures. Moreover, PAP-FcP and PAP-FcKP exhibited a high association rate with human FcγR and FcRn. Vaccination of mice with both PAP-FcP and PAP-FcKP resulted in increased total IgG against PAP and enhanced activation of CD4+ T cells, comparable to mice immunized with PAP, which served as a positive control. These findings indicate that both plant-derived MPs can effectively induce adaptive immunity, positioning them as promising candidates for prostate cancer vaccines. Overall, plants expressing PAP-Fc and PAP-FcK represent a viable production system for antigenic macromolecule-based prostate cancer vaccines.

Male↗
PubMed2003

A molecular switch between alternative conformational states in the complex of Ran and importin beta1.

Several million macromolecules are exchanged each minute between the nucleus and cytoplasm by receptor-mediated transport. Most of this traffic is controlled by the small GTPase Ran, which regulates assembly and disassembly of the receptor-cargo complexes in the appropriate cellular compartment. Here we applied dynamic force spectroscopy to study the interaction of Ran with the nuclear import receptor importin beta1 (impbeta) at the single-molecule level. We found that the complex alternates between two distinct conformational states of different adhesion strength. The application of an external mechanical force shifts equilibrium toward one of these states by decreasing the height of the interstate activation energy barrier. The other state can be stabilized by a functional Ran mutant that increases this barrier. These results support a model whereby functional control of Ran-impbeta is achieved by a population shift between pre-existing alternative conformations.

Guanosine Diphosphate↗
PubMed2002

Ca(++)-dependent vesicle release from erythrocytes involves stomatin-specific lipid rafts, synexin (annexin VII), and sorcin.

Cytosolic Ca(++) induces the shedding of microvesicles and nanovesicles from erythrocytes. Atomic force microscopy was used to determine the sizes of these vesicles and to resolve the patchy, fine structure of the microvesicle membrane. The vesicles are highly enriched in glycosyl phosphatidylinositol-linked proteins, free of cytoskeletal components, and depleted of the major transmembrane proteins. Both types of vesicles contain 2 as-yet-unrecognized red cell proteins, synexin and sorcin, which translocate from the cytosol to the membrane upon Ca(++) binding. In nanovesicles, synexin and sorcin are the most abundant proteins after hemoglobin. In contrast, the microvesicles are highly enriched in stomatin. The membranes of both microvesicles and nanovesicles contain lipid rafts. Stomatin is the major protein of the microvesicular lipid rafts, whereas synexin and sorcin represent the major proteins of the nanovesicular rafts in the presence of Ca(++). Interestingly, the raft proteins flotillin-1 and flotillin-2 are not found in the vesicles but remain in the red cell membrane. These data indicate the presence of different types of lipid rafts in the erythrocyte membrane with distinct fates after Ca(++) entry. Synexin, which is known to be vital to the process of membrane fusion, is suggested to be a key component in the process of vesicle release from erythrocytes.

Acetylcholinesterase↗
PubMed2002

Single molecule recognition of protein binding epitopes in brush border membranes by force microscopy.

Sidedness and accessibility of protein epitopes in intact brush border membrane vesicles were analyzed by detecting single molecule interaction forces using molecular recognition force microscopy in aqueous physiological solutions. Frequent antibody-antigen recognition events were observed with a force microscopy tip carrying an antibody directed against the periplasmically located gamma-glutamyltrans- peptidase, suggesting a right side out orientation of the vesicles. Phlorizin attached to the tips bound to NA+/D-glucose cotransporter molecules present in the vesicles. The recognition was sodium dependent and inhibited by free phlorizin and D-glucose, and revealed an apparent K(D) of 0.2 microM. Binding events were also observed with an antibody directed against the epitope aa603-aa630 close to the C terminus of the transporter. In the presence of phlorizin the probability of antibody binding was reduced but the most probable unbinding force f(u) = 100 pN remained unchanged. In the presence of D-glucose and sodium, however, both the binding probability and the most probable binding force (f(u) = 50 pN) were lower than in its absence. These studies demonstrate that molecular recognition force microscopy is a versatile tool to probe orientation and conformational changes of epitopes of membrane components during binding and trans-membrane transport.

Animals↗
PubMed2002

Biomolecular force measurements and the atomic force microscope.

The atomic force microscope (AFM) is a surface-sensitive instrument capable of imaging biological samples at nanometer resolution in all environments including liquids. The sensitivity of the AFM cantilever, to forces in the pico Newton range, has been exploited to measure breakaway forces between biomolecules and to measure folding-unfolding forces within single proteins. By attaching specific antibodies to cantilevers the simultaneous imaging of target antigens and identification of antigen-antibody interactions have been demonstrated.

Microscopy, Atomic Force↗
PubMedDate not supplied

Dynamic force microscopy imaging of native membranes.

We employed magnetic ACmode atomic force microscopy (MACmode AFM) as a novel dynamic force microscopy method to image surfaces of biological membranes in their native environments. The lateral resolution achieved under optimized imaging conditions was in the nanometer range, even when the sample was only weakly attached to the support. Purple membranes (PM) from Halobacterium salinarum were used as a test standard for topographical imaging. The hexagonal arrangement of the bacteriorhodopsin trimers on the cytoplasmic side of PM was resolved with 1.5nm lateral accuracy, a resolution similar to images obtained in contact and tapping-mode AFM. Human rhinovirus 2 (HRV2) particles were attached to mica surfaces via nonspecific interactions. The capsid structure and 2nm sized protein loops of HRV2 were routinely obtained without any displacement of the virus. Globular and filamentous structures on living and fixed endothelial cells were observed with a resolution of 5-20nm. These examples show that MACmode AFM is a favorable method in studying the topography of soft and weakly attached biological samples with high resolution under physiological conditions.

Capsid↗