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Cryo‐electron microscopic structure of SecA bound to the 70S ribosome (752.1)
Author(s) -
Bhushan Shashi
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.752.1
Subject(s) - dimer , ribosome , cytoplasm , biophysics , chemistry , context (archaeology) , monomer , crystallography , biochemistry , biology , rna , gene , paleontology , organic chemistry , polymer
SecA is an ATP‐dependent molecular motor pumping the secretory and outer membrane proteins across the cytoplasmic membrane in bacteria. SecA associates with the protein conducting channel, the hetrotrimeric SecYEG complex, in a so‐called post‐translational manner. Although, SecA can form functional dimers and high‐resolution crystal structures exist of both the monomer and dimer, the true oligomeric state of SecA remains controversial. We have determined the cryo‐electron microscopy structures of SecA bound to the ribosome. Our results show that not only a monomeric SecA binds to the ribosome but also two copies of SecA can be observed which form an elongated dimer. Results will be discussed in the context of a direct co‐translational role of SecA during protein translocation.