Characterization of the SRP68/72 interface of human signal recognition particle by systematic site-directed mutagenesis.

ABSTRACT: The signal recognition particle (SRP) is a ribonucleoprotein complex which is crucial for the delivery of proteins to cellular membranes. Among the six proteins of the eukaryotic SRP, the two largest, SRP68 and SRP72, form a stable SRP68/72 heterodimer of unknown structure which is required for SRP function. Fragments 68e' (residues 530 to 620) and 72b' (residues 1 to 166) participate in the SRP68/72 interface. Both polypeptides were expressed in Escherichia coli and assembled into a complex which was stable at high ionic strength. Disruption of 68e'/72b' and SRP68/72 was achieved by denaturation using moderate concentrations of urea. The four predicted tetratricopeptide repeats (TPR1 to TPR4) of 72b' were required for stable binding of 68e'. Site-directed mutagenesis suggested that they p

SUBMITTER: Iakhiaeva E 

PROVIDER: S-EPMC2786981 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature