TY - JOUR
T1 - Protein SRP54 of human signal recognition particle
T2 - Cloning, expression, and comparative analysis of functional sites
AU - Gowda, Krishne
AU - Black, Shaun D.
AU - Moeller, Ines
AU - Sakakibara, Yoichi
AU - Liu, Ming Cheh
AU - Zwieb, Christian
N1 - Funding Information:
We thank K. Ajay Sharma for help with recombinant protein expression in insect cells, Kimberly Chittenden and Kerfoot P. Walker III for expert technical assistance, and Martin Wiedmann for advice in the photoaffinity labeling with nascent signal peptides. This work was supported by NIH grant GM-49034 to C.Z.
PY - 1998/1/30
Y1 - 1998/1/30
N2 - Signal recognition particle (SRP) plays a critical role in the targeting of secretory proteins to cellular membranes. An essential component of SRP is the protein SRP54, which interacts not only with the nascent signal peptide, but also with the SRP RNA. To understand better how protein targeting occurs in the human system, the human SRP54 gene was cloned, sequenced, and the protein was expressed in bacteria and insect cells. Recombinant SRP54 was purified from both sources. The protein bound to SRP RNA in the presence of protein SRP19, and associated with the signal peptide of in vitro translated pre-prolactin. Comparative sequence analysis of human SRP54 with homologs from all three phylogenetic domains was combined with high-stringency protein secondary structure prediction. A conserved RNA-binding loop was predicted in the largely helical M-domain of SRP54. Contrary to general belief, the unusually high number of methionine residues clustered outside the predicted helices, thus indicating a mechanism of signal peptide recognition that may involve methionine-rich loops.
AB - Signal recognition particle (SRP) plays a critical role in the targeting of secretory proteins to cellular membranes. An essential component of SRP is the protein SRP54, which interacts not only with the nascent signal peptide, but also with the SRP RNA. To understand better how protein targeting occurs in the human system, the human SRP54 gene was cloned, sequenced, and the protein was expressed in bacteria and insect cells. Recombinant SRP54 was purified from both sources. The protein bound to SRP RNA in the presence of protein SRP19, and associated with the signal peptide of in vitro translated pre-prolactin. Comparative sequence analysis of human SRP54 with homologs from all three phylogenetic domains was combined with high-stringency protein secondary structure prediction. A conserved RNA-binding loop was predicted in the largely helical M-domain of SRP54. Contrary to general belief, the unusually high number of methionine residues clustered outside the predicted helices, thus indicating a mechanism of signal peptide recognition that may involve methionine-rich loops.
KW - Protein secretion
KW - Protein targeting
KW - RNA-protein interactions
KW - Signal peptide
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U2 - 10.1016/S0378-1119(97)00627-6
DO - 10.1016/S0378-1119(97)00627-6
M3 - Article
C2 - 9511762
AN - SCOPUS:0032579343
VL - 207
SP - 197
EP - 207
JO - Gene
JF - Gene
SN - 0378-1119
IS - 2
ER -