HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mura, C. Articles by Eisenberg, D. Search for Related Content PubMed PubMed Citation Articles by Mura, C. Articles by Eisenberg, D. Social Bookmarking                   What's this?

The oligomerization and ligand-binding properties of Sm-like archaeal proteins (SmAPs)

¹ Howard Hughes Medical Institute, Molecular Biology Institute, and UCLA-DOE Center for Genomics and Proteomics, Los Angeles, California 90095-1570, USA
² Department of Chemistry and Biochemistry and Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California 90095, USA

Reprint requests to: David Eisenberg, Department of Chemistry and Biochemistry and Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA 90095, USA; e-mail: david{at}mbi.ucla.edu; fax: (310) 206-3914.

Intron splicing is a prime example of the many types of RNA processing catalyzed by small nuclear ribonucleoprotein (snRNP) complexes. Sm proteins form the cores of most snRNPs, and thus to learn principles of snRNP assembly we characterized the oligomerization and ligand-binding properties of Sm-like archaeal proteins (SmAPs) from Pyrobaculum aerophilum (Pae) and Methanobacterium thermautotrophicum (Mth). Ultracentrifugation shows that Mth SmAP1 is exclusively heptameric in solution, whereas Pae SmAP1 forms either disulfide-bonded 14-mers or sub-heptameric states (depending on the redox potential). By electron microscopy, we show that Pae and Mth SmAP1 polymerize into bundles of well ordered fibers that probably form by head-to-tail stacking of heptamers. The crystallographic results reported here corroborate these findings by showing heptamers and 14-mers of both Mth and Pae SmAP1 in four new crystal forms. The 1.9 Å-resolution structure of Mth SmAP1 bound to uridine-5'-monophosphate (UMP) reveals conserved ligand-binding sites. The likely RNA binding site in Mth agrees with that determined for Archaeoglobus fulgidus (Afu) SmAP1. Finally, we found that both Pae and Mth SmAP1 gel-shift negatively supercoiled DNA. These results distinguish SmAPs from eukaryotic Sm proteins and suggest that SmAPs have a generic single-stranded nucleic acid-binding activity.

Keywords: Ribonucleoprotein; Sm protein; protein polymerization; uridine binding; OB fold

Abbreviations: Afu, Archaeoglobus fulgidus • DTT, dithiothreitol • EM, electron microscopy • MPD, 2-methyl-2,4-pentanediol • Mth, Methanobacterium thermautotrophicum • NCS, noncrystallographic symmetry • nt, nucleotide • OB-fold, oligosaccharide/oligonucleotide-binding fold • Pae, Pyrobaculum aerophilum • ss(D/R)NA, single-stranded (D/R)NA • SmAP, Sm-like archaeal protein • snRNP, small nuclear ribonucleoprotein • UMP, uridine-5'-monophosphate • wt, wild type

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				J. S. Nielsen, A. Boggild, C. B.F. Andersen, G. Nielsen, A. Boysen, D. E. Brodersen, and P. Valentin-Hansen An Hfq-like protein in archaea: Crystal structure and functional characterization of the Sm protein from Methanococcus jannaschii RNA, December 1, 2007; 13(12): 2213 - 2223. [Abstract] [Full Text] [PDF]

				V. Arluison, S. Hohng, R. Roy, O. Pellegrini, P. Regnier, and T. Ha Spectroscopic observation of RNA chaperone activities of Hfq in post-transcriptional regulation by a small non-coding RNA Nucleic Acids Res., February 16, 2007; 35(3): 999 - 1006. [Abstract] [Full Text] [PDF]

				S. Tharun, D. Muhlrad, A. Chowdhury, and R. Parker Mutations in the Saccharomyces cerevisiae LSM1 Gene That Affect mRNA Decapping and 3' End Protection Genetics, May 1, 2005; 170(1): 33 - 46. [Abstract] [Full Text] [PDF]

				C. Mura, M. Phillips, A. Kozhukhovsky, and D. Eisenberg Structure and assembly of an augmented Sm-like archaeal protein 14-mer PNAS, April 15, 2003; 100(8): 4539 - 4544. [Abstract] [Full Text] [PDF]