A solution to one of immunology's long-standing mysteries may emerge from a Weizmann Institute study reported in the Proceedings of the National Academy of Sciences (June 12, Vol. 94, p. 6335).
The mystery concerns antibodies, the immune system's "weapons" whose task is to attack foreign proteins, such as those contained in disease-causing microorganisms. Each antibody is usually exquisitely tailored to bind with a particular protein, fitting into its crevices like a key into a lock. Yet some antibodies work like "master keys," attaching themselves to numerous proteins. What is the function and mechanism of these baffling molecules?
Prof. Meir Wilchek, doctoral student Boris Tchernychev and Dr. Shmuel Cabilly of the Membrane Research and Biophysics Department found that the "master-key" antibodies interact with proline, the amino acid present on proteins and protein fragments at the site where these molecules form a loop or a sharp curve. When a protein has to be removed because it is defective or is no longer needed, these structural elements become exposed, the scientists suggest. The exposure, in turn, allows the master-key antibody to bind to the loop or curve and "escort" the protein out of the body.
This research provides a scientific basis for the theory that master-key antibodies may serve to "clean out" a broad range of unneeded proteins from the body without interfering with those proteins whose activity is beneficial.
Prof. Wilchek holds the Marc R. Gutwirth Chair of Molecular Biology. The study was supported by the Lynne and William Frankel Fund for the Diagnosis and Treatment of Ovarian and Breast Cancer, and the Minerva Foundation.
###
Journal
Proceedings of the National Academy of Sciences