5k94
Deletion-Insertion Chimera of MBP with the Preprotein Cross-Linking Domain of the SecA ATPase
Structural highlights
FunctionMALE_ECOLI Involved in the high-affinity maltose membrane transport system MalEFGK. Initial receptor for the active transport of and chemotaxis toward maltooligosaccharides.SECA_ECOLI Required for protein export, interacts with the SecYEG preprotein conducting channel. SecA has a central role in coupling the hydrolysis of ATP to the transfer of proteins into and across the cell membrane, serving both as a receptor for the preprotein-SecB complex and as an ATP-driven molecular motor driving the stepwise translocation of polypeptide chains across the membrane.[1] Publication Abstract from PubMedWe coupled peptides from a CNBr 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 NBD1 and NBD2) 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. Characterization of a polypeptide-binding site in the DEAD Motor of the SecA ATPase.,Khalili Yazdi A, Namjoshi S, Hackett J, Ghonaim N, Shilton BH FEBS Lett. 2017 Oct;591(20):3378-3390. doi: 10.1002/1873-3468.12832. Epub 2017, Sep 12. PMID:28862749[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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