ISDA

Entry Detail

PDB ID:

1I8F

Keywords:

STRUCTURAL GENOMICS

Title:

THE CRYSTAL STRUCTURE OF A HEPTAMERIC ARCHAEAL SM PROTEIN: IMPLICATIONS FOR THE EUKARYOTIC SNRNP CORE

Biological Source:

Source Organism:

Pyrobaculum aerophilum

Host Organism:

Escherichia coli BL21(DE3)

PDB Version:

Deposition Date:

2001-03-14

Release Date:

2001-05-16

Method Details:

Experimental Method:

X-RAY DIFFRACTION

Resolution:

1.75 Å

R-Value Free:

0.26

R-Value Work:

0.23

Space Group:

C 1 2 1

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Macromolecular Entities

Protein Blast

Polymer Type:polypeptide(L)
Description:PUTATIVE SNRNP SM-LIKE PROTEIN
Chain IDs:A, B, C, D, E, F, G
Chain Length:81
Number of Molecules:7
Biological Source:Pyrobaculum aerophilum

UniProt ID:Q8ZYG5 Pfam ID:PF01423

Ligand Molecules

GOL

Primary Citation

The crystal structure of a heptameric archaeal Sm protein: Implications for the eukaryotic snRNP core.

Mura, C, Cascio, D, Sawaya, M.R, Eisenberg, D.S.Show

Proc.Natl.Acad.Sci.USA 98 5532 5537 (2001)

PMID: 11331747 DOI: 10.1073/pnas.091102298

Abstact

Sm proteins form the core of small nuclear ribonucleoprotein particles (snRNPs), making them key components of several mRNA-processing assemblies, including the spliceosome. We report the 1.75-A crystal structure of SmAP, an Sm-like archaeal protein that forms a heptameric ring perforated by a cationic pore. In addition to providing direct evidence for such an assembly in eukaryotic snRNPs, this structure (i) shows that SmAP homodimers are structurally similar to human Sm heterodimers, (ii) supports a gene duplication model of Sm protein evolution, and (iii) offers a model of SmAP bound to single-stranded RNA (ssRNA) that explains Sm binding-site specificity. The pronounced electrostatic asymmetry of the SmAP surface imparts directionality to putative SmAP-RNA interactions.

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Primary Citation of related structures