There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
Modification of cellular proteins by the ubiquitin-like protein SUMO is essential
for nuclear processes and cell cycle progression in yeast. The Ulp1 protease catalyzes
two essential functions in the SUMO pathway: (1) processing of full-length SUMO to
its mature form and (2) deconjugation of SUMO from targeted proteins. Selective reduction
of the proteolytic reaction produced a covalent thiohemiacetal transition state complex
between a Ulp1 C-terminal fragment and its cellular substrate Smt3, the yeast SUMO
homolog. The Ulp1-Smt3 crystal structure and functional testing of elements within
the conserved interface elucidate determinants of SUMO recognition, processing, and
deconjugation. Genetic analysis guided by the structure further reveals a regulatory
element N-terminal to the proteolytic domain that is required for cell growth in yeast.