ausblenden:
Schlagwörter:
Fab fragment, human hepsin antibody, induced
conformational change, prostate cancer, transmembrane serine
protease, X-ray structure
Zusammenfassung:
Hepsin is a type II transmembrane serine protease that is expressed
in several human tissues.Overexpression of hepsin has been found
to correlate with tumour progression and metastasis, which is so
far best studied for prostate cancer, where more than 90% of
such tumours show this characteristic. To enable improved future
patient treatment, we have developed a monoclonal humanized
antibody that selectively inhibits human hepsin and does not
inhibit other related proteases. We found that our antibody,
hH35, potently inhibits hepsin enzymatic activity at nanomolar
concentrations.Kinetic characterization revealed non-linear, slow,
tight-binding inhibition. This correlates with the crystal structure
we obtained for the human hepsin–hH35 antibody Fab fragment
complex, which showed that the antibody binds hepsin around
α3-helix, located far from the active centre. The unique allosteric
mode of inhibition of hH35 is distinct from the recently described
HGFA (hepatocyte growth factor activator) allosteric antibody inhibition.
We further explain how a small change in the antibody
design induces dramatic structural rearrangements in the hepsin
antigen upon binding, leading to complete enzyme inactivation.
