Targeted proteolysis is a hallmark of life.It is especially important in long-lived cells that can be found in higher eukaryotes,like plants.This task is mainly fulfilled by the ubiquitin–proteasome system.Thus,prote...Targeted proteolysis is a hallmark of life.It is especially important in long-lived cells that can be found in higher eukaryotes,like plants.This task is mainly fulfilled by the ubiquitin–proteasome system.Thus,proteolysis by the 26S proteasome is vital to development,immunity,and cell division.Although the yeast and animal proteasomes are well characterized,there is only limited information on the plant proteasome.We determined the first plant 26S proteasome structure from Spinacia oleracea by single-particle electron cryogenic microscopy at an overall resolution of 3.3 A°.We found an almost identical overall architecture of the spinach proteasome compared with the known structures from mammals and yeast.Nevertheless,we noticed a structural difference in the proteolytic active b1 subunit.Furthermore,we uncovered an unseen compression state by characterizing the proteasome’s conformational landscape.We suspect that this new conformation of the 20S core protease,in correlation with a partial opening of the unoccupied gate,may contribute to peptide release after proteolysis.Our data provide a structural basis for the plant proteasome,which is crucial for further studies.展开更多
基金D.L.B.and N.G.B.are supported by NIH R35GM128855 and the Univer-sity Cancer Research Fund(UCRF)H.D.T.and B.F.were supported by NIH grant R01GM125769The IMP,the whole Haselbach lab,and espe-cially S.K.are supported by Boehringer Ingelheim.
文摘Targeted proteolysis is a hallmark of life.It is especially important in long-lived cells that can be found in higher eukaryotes,like plants.This task is mainly fulfilled by the ubiquitin–proteasome system.Thus,proteolysis by the 26S proteasome is vital to development,immunity,and cell division.Although the yeast and animal proteasomes are well characterized,there is only limited information on the plant proteasome.We determined the first plant 26S proteasome structure from Spinacia oleracea by single-particle electron cryogenic microscopy at an overall resolution of 3.3 A°.We found an almost identical overall architecture of the spinach proteasome compared with the known structures from mammals and yeast.Nevertheless,we noticed a structural difference in the proteolytic active b1 subunit.Furthermore,we uncovered an unseen compression state by characterizing the proteasome’s conformational landscape.We suspect that this new conformation of the 20S core protease,in correlation with a partial opening of the unoccupied gate,may contribute to peptide release after proteolysis.Our data provide a structural basis for the plant proteasome,which is crucial for further studies.
