Complexes with truncated RNAs from the large domain of Archaeoglobus fulgidus signal recognition particle

Protein SRP19 is an important component of the signal recognition particle (SRP) as it promotes assembly of protein SRP54 with SRP RNA and recognizes a tetranucleotide loop. Structural features acid RNA binding activities of SRP19 of the hyperthermophilic archaeon Archaeoglobus fulgidus were investi gated. An updated alignment of SRP 19 sequences predicted three conserved r egions and two alpha -helices, With Af-SRP RNA the Af-SRP54 protein assembl ed into an A.fulgidus SRP which remained intact For many hours. stable comp lexes were formed between Af-SRP19 and truncated SRP RNAs, including a 36-r esidue fragment representing helix 6 of A. fulgidus SRP RNA. (C) 2001 Feder ation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.