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Characterization of a polypeptide‐binding site in the DEAD Motor of the SecA ATP ase
Author(s) -
Khalili Yazdi Aliakbar,
Namjoshi Sarita,
Hackett Jesse,
Ghonaim Nour,
Shilton Brian H.
Publication year - 2017
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 - 10.1002/1873-3468.12832
Subject(s) - maltose binding protein , surface plasmon resonance , peptide , chemistry , cyclic nucleotide binding domain , binding site , atpase , biochemistry , plasma protein binding , binding protein , binding domain , peptide sequence , biophysics , biology , enzyme , fusion protein , recombinant dna , gene , nanotechnology , materials science , nanoparticle
We coupled peptides from a CNB r digest of signal‐sequenceless maltose‐binding protein ( MBP ) to a surface plasmon resonance chip. SecA‐N95, SecA‐N68, and SecA‐ DM (which consists of only the DEAD Motor domains NBD 1 and NBD 2) bound to the immobilized peptides; ADP weakened the binding. SecA‐ DM , which lacks the ‘preprotein cross‐linking domain’ ( PPXD ), displayed the most extensive binding, while an MBP ‐ PPXD chimera showed no binding, demonstrating that the PPXD does not contribute to the binding. We characterized the sequence specificity using oriented peptide libraries; these results enabled synthesis of a 20‐residue peptide that was used to recapitulate the results obtained with MBP ‐derived peptides. This study shows that there is a promiscuous and nucleotide‐modulated peptide‐binding site in the DEAD Motor domains of SecA.