Protein SRP54 of human signal recognition particle: Cloning, expression, and comparative analysis of functional sites

Krishne Gowda, Shaun D. Black, Ines Moeller, Yoichi Sakakibara, Ming Cheh Liu, Christian Zwieb

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)197-207
Number of pages11
JournalGene
Volume207
Issue number2
DOIs
StatePublished - Jan 30 1998
Externally publishedYes

Keywords

  • Protein secretion
  • Protein targeting
  • RNA-protein interactions
  • Signal peptide

ASJC Scopus subject areas

  • Genetics

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