Signal-sequence induced conformational changes in the signal recognition particle
2015 (English)In: Nature Communications, ISSN 2041-1723, Vol. 6, 7163Article in journal (Refereed) Published
Co-translational protein targeting is an essential, evolutionarily conserved pathway for delivering nascent proteins to the proper cellular membrane. In this pathway, the signal recognition particle (SRP) first recognizes the N-terminal signal sequence of nascent proteins and subsequently interacts with the SRP receptor. For this, signal sequence binding in the SRP54 M domain must be effectively communicated to the SRP54 NG domain that interacts with the receptor. Here we present the 2.9 angstrom crystal structure of unbound- and signal sequence bound SRP forms, both present in the asymmetric unit. The structures provide evidence for a coupled binding and folding mechanism in which signal sequence binding induces the concerted folding of the GM linker helix, the finger loop, and the C-terminal alpha helix alpha M6. This mechanism allows for a high degree of structural adaptability of the binding site and suggests how signal sequence binding in the M domain is coupled to repositioning of the NG domain.
Place, publisher, year, edition, pages
2015. Vol. 6, 7163
IdentifiersURN: urn:nbn:se:umu:diva-106604DOI: 10.1038/ncomms8163ISI: 000357166200002PubMedID: 26051119OAI: oai:DiVA.org:umu-106604DiVA: diva2:843312