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Escherichia coli SecA truncated at its termini is functional and dimeric
Author(s) -
Karamanou Spyridoula,
Sianidis Giorgos,
Gouridis Giorgos,
Pozidis Charalambos,
Papanikolau Yiannis,
Papanikou Efrosyni,
Economou Anastassios
Publication year - 2005
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.01.025
Subject(s) - translocase , escherichia coli , mutant , atpase , chromosomal translocation , c terminus , biochemistry , chemistry , biology , ctd , biophysics , enzyme , gene , amino acid , oceanography , geology
Terminal residues in SecA, the dimeric ATPase motor of bacterial preprotein translocase, were proposed to be required for function and dimerization. To test this, we generated truncation mutants of the 901aa long SecA of Escherichia coli . We now show that deletions of carboxy‐terminal domain (CTD), the extreme CTD of 70 residues, or of the N‐terminal nonapeptide or of both, do not compromise protein translocation or viability. Deletion of additional C‐terminal residues upstream of CTD compromised function. Functional truncation mutants like SecA9‐861 are dimeric, conformationally similar to SecA, fully competent for nucleotide and SecYEG binding and for ATP catalysis. Our data demonstrate that extreme terminal SecA residues are not essential for SecA catalysis and dimerization.