Structural features of the plant N ‐recognin ClpS1 and sequence determinants in its targets that govern substrate selection

AbstractIn the N ‐degron pathway of protein degradation ofEscherichia coli, the N ‐recognin ClpS identifies substrates bearing N‐terminal phenylalanine, tyrosine, tryptophan, or leucine and delivers them to the Clp protease. Chloroplasts contain the Clp system, but whether chloroplastic ClpS1 adheres to the same constraints is unknown. Moreover, the structural underpinnings o f substrate recognition are not completely defined. We show that ClpS1 recognizes canonical residues of theE. coli N ‐degron pathway. The residue in second position influences recognition (especially in N‐terminal ends starting with leucine). N‐terminal acetylation abrogates recognition. ClpF, a ClpS1‐interacting partner, does not alter its specificity. Substrate binding provokes local remodeling of residu es in the substrate‐binding cavity of ClpS1. Our work strongly supports the existence of a chloroplastic N‐degron pathway.

Source: FEBS Letters - April 1, 2021 Category: Biochemistry Authors: Dianela Aguilar Lucero, Alejo Cantoia, Carolina S ánchez‐López, Andrés Binolfi, Axel Mogk, Eduardo A. Ceccarelli, Germán L. Rosano Tags: RESEARCH LETTER Source Type: research