Ruth Nussinov (Hebrew: פרופסורית רותי נוסינוב) is an Israeli-American biologist born in Rehovot who works as a professor in the Department of Human Genetics, School of Medicine at Tel Aviv University and is the senior principal scientist and principal investigator at the National Cancer Institute, National Institutes of Health.

In 1999 Nussinov published the transformational concept that all conformations preexist—even if the crystal captures only one—and that evolution harnesses their dynamic interconversion for function, dispelling the dogma that only the wild-type shape is relevant.

[6][7][8][9] Nussinov suggested a vastly different scenario from the-then dogma of two, “open” and “closed" conformations proposed by Monod, Wyman, and Changeux.

This foundational “conformational selection and population shift” idea as an alternative to the “induced fit” text-book model explains the mechanism of molecular recognition.

As Nussinov and others have shown since, this paradigm helps unravel diverse processes as signaling, regulation, and aggregation in amyloid diseases, and oncogenic transformation, contributing to extraordinary advancements in understanding structure and function.

[4] It has since been taught in bioinformatics and computational biology classes in Europe and the US, it is included in books, and exploited in multiple software packages.

The paradigm that she introduced has impacted the scientific community's views and strategies in allosteric drug design, biomolecular engineering, molecular evolution, and cell signaling.

The profound significance, and advance was also heralded in Science as innovating on the decades-old concepts, noting that "although textbooks have championed the induced fit mechanism for more than 50 years, data (especially NMR) unequivocally support the powerful paradigm for diverse biological processes".