1n9s
From Proteopedia
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Crystal structure of yeast SmF in spacegroup P43212
Overview
Sm and Sm-like proteins are key components of small ribonucleoproteins, involved in many RNA and DNA processing pathways. In eukaryotes, these, complexes contain seven unique Sm or Sm-like (Lsm) proteins assembled as, hetero-heptameric rings, whereas in Archaea and bacteria six or, seven-membered rings are made from only a single polypeptide chain. Here, we show that single Sm and Lsm proteins from yeast also have the capacity, to assemble into homo-oligomeric rings. Formation of homo-oligomers by the, spliceosomal small nuclear ribonucleoprotein components SmE and SmF, preclude hetero-interactions vital to formation of functional small, nuclear RNP complexes in vivo. To better understand these unusual, complexes, we have determined the crystal structure of the homomeric, assembly of the spliceosomal protein SmF. Like its archaeal/bacterial, homologs, the SmF complex forms a homomeric ring but in an entirely novel, arrangement whereby two heptameric rings form a co-axially stacked dimer, via interactions mediated by the variable loops of the individual SmF, protein chains. Furthermore, we demonstrate that the homomeric assemblies, of yeast Sm and Lsm proteins are capable of binding not only to oligo(U), RNA but, in the case of SmF, also to oligo(dT) single-stranded DNA.
About this Structure
1N9S is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Homomeric ring assemblies of eukaryotic Sm proteins have affinity for both RNA and DNA. Crystal structure of an oligomeric complex of yeast SmF., Collins BM, Cubeddu L, Naidoo N, Harrop SJ, Kornfeld GD, Dawes IW, Curmi PM, Mabbutt BC, J Biol Chem. 2003 May 9;278(19):17291-8. Epub 2003 Mar 4. PMID:12618433
Page seeded by OCA on Tue Nov 20 22:05:07 2007
