INFLUENCE OF SUBSTITUTIONS OF Isu1 RESIDUES ON BINDING TO Jac1 PROTEIN

Abstract

The iron-sulfur (Fe/S) clusters are the most ancient co-factors of proteins involved in the most essential processes in bacterial systems and yeast, such as Saccharomyces cerevisiae. The main protein involved in the Fe/S cluster transfer is the Iron sulfur cluster assembly protein 1 (Isu1), which interacts with Jac1 during one of the stages of the Fe/S cluster biogenesis cycle forming a binary complex. In this work, the interaction interface of Isu1 was investigated by selective substitutions of amino-acid residues to understand their role in binding to the Jac1 protein. An initial alanine scan was done to limit the number of possible residues subjected to the replacement and to confirm the previously obtained results. Then, MD simulations using the coarse-grained UNRES force field were run for two selected mutants: L₆₃V₇₂F₉₄ and L₆₃V₆₄G₆₅D₇₁. The analysis of the dynamics and interaction patterns of the Isu1-Jac1 complexes confirmed that the investigated residues played an important role in their binding.