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SacY is the prototype of a family of regulatory proteins able to prevent transcription termination. It interacts with a 29 nucleotide RNA sequence able to fold into a stem-loop structure and partially overlapping with a terminator sequence located in the 5' leader mRNA region of the gene it controls. We show here that the N-terminal fragment of SacY,(More)
Numerous RNA-binding proteins have modular structures, comprising one or several copies of a selective RNA-binding domain generally coupled to an auxiliary domain that binds RNA non-specifically. We have built and compared homology-based models of the cold-shock domain (CSD) of the Xenopus protein, FRGY2, and of the third RNA recognition motif (RRM) of the(More)
The wac gene product (gpwac) or fibritin of bacteriophage T4 forms the six fibers that radiate from the phage neck. During phage morphogenesis these whiskers bind the long tail fibers (LTFs) and facilitate their attachment to the phage baseplate. After the cell lysis, the gpwac fibers function as part of an environmental sensing device that retains the LTFs(More)
Reg proteins are expressed in various organs and are involved in cancers and neurodegenerative diseases. They display a typical C-type lectin-like domain but possess additional highly conserved amino acids. By studying human databases and Expressed Sequence Tags library, we identified a new member called PAP IB. Using probabilistic approaches, we(More)
In archaeal rRNAs, the isomerization of uridine into pseudouridine (Psi) is achieved by the H/ACA sRNPs and the minimal set of proteins required for RNA:Psi-synthase activity is the aCBF5-aNOP10 protein pair. The crystal structure of the aCBF5-aNOP10 heterodimer from Pyrococcus abyssi was solved at 2.1 A resolution. In this structure, protein aNOP10 has an(More)
The ribosomal L7Ae protein of archaea has the peculiarity to be a component of the C/D and H/ACA snRNPs, that guide rRNA post-transcriptional modifications. Its yeast (Snu13p) and human (15.5kDa protein) homologs are only found in C/D snoRNPs and the (U4/U6, U5) spliceosomal tri-snRNP. By using a large variety of RNAs, we compared the RNA-binding(More)
The L7Ae sRNP core protein from Pyrococcus abyssii was crystallized using the sitting-drop vapour-diffusion method. Crystals were obtained in the presence of MgCl(2), PEG 2000 MME and acetate buffer at pH 4.0. A native data set has been collected at 2.9 A resolution using a rotating-anode generator at room temperature. Crystals belong to the orthorhombic(More)
The ubiquitous Hsp90 chaperone participates in snoRNP and RNA polymerase assembly through interaction with the R2TP complex. This complex includes the proteins Tah1, Pih1, Rvb1, and Rvb2. Tah1 bridges Hsp90 to R2TP. Its minimal TPR domain includes two TPR motifs and a capping helix. We established the high-resolution solution structures of Tah1 free and in(More)
In vitro, assembly of box C/D small nucleolar ribonucleoproteins (snoRNPs) involves the sequential recruitment of core proteins to snoRNAs. In vivo, however, assembly factors are required (NUFIP, BCD1, and the HSP90-R2TP complex), and it is unknown whether a similar sequential scheme applies. In this paper, we describe systematic quantitative stable isotope(More)
The yeast Snu13p protein and its 15.5K human homolog both bind U4 snRNA and box C/D snoRNAs. They also bind the Rsa1p/NUFIP assembly factor, proposed to scaffold immature snoRNPs and to recruit the Hsp90-R2TP chaperone complex. However, the nature of the Snu13p/15.5K-Rsa1p/NUFIP interaction and its exact role in snoRNP assembly remained to be elucidated. By(More)