Co-evolution of Two GTPases Enables Efficient Protein Targeting in an RNA-less Chloroplast Signal Recognition Particle Pathway.

ABSTRACT: The signal recognition particle (SRP) is an essential ribonucleoprotein particle that mediates the co-translational targeting of newly synthesized proteins to cellular membranes. The SRP RNA is a universally conserved component of SRP that mediates key interactions between two GTPases in SRP and its receptor, thus enabling rapid delivery of cargo to the target membrane. Notably, this essential RNA is bypassed in the chloroplast (cp) SRP of green plants. Previously, we showed that the cpSRP and cpSRP receptor GTPases (cpSRP54 and cpFtsY, respectively) interact efficiently by themselves without the SRP RNA. Here, we explore the molecular mechanism by which this is accomplished. Fluorescence analyses showed that, in the absence of SRP RNA, the M-domain of cpSRP54 both accelerates and stabiliz

SUBMITTER: Chandrasekar S 

PROVIDER: S-EPMC5217696 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature