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PDBsum entry 2f9d
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RNA binding protein
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PDB id
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2f9d
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References listed in PDB file
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Key reference
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Title
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Crystal structure of a core spliceosomal protein interface.
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Authors
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M.J.Schellenberg,
R.A.Edwards,
D.B.Ritchie,
O.A.Kent,
M.M.Golas,
H.Stark,
R.Lührmann,
J.N.Glover,
A.M.Macmillan.
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Ref.
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Proc Natl Acad Sci U S A, 2006,
103,
1266-1271.
[DOI no: ]
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PubMed id
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Abstract
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The precise excision of introns from precursor mRNAs (pre-mRNAs) in eukaryotes
is accomplished by the spliceosome, a complex assembly containing five small
nuclear ribonucleoprotein (snRNP) particles. Human p14, a component of the
spliceosomal U2 and U11/U12 snRNPs, has been shown to associate directly with
the pre-mRNA branch adenosine early in spliceosome assembly and within the fully
assembled spliceosome. Here we report the 2.5-A crystal structure of a complex
containing p14 and a peptide derived from the p14-associated U2 snRNP component
SF3b155. p14 contains an RNA recognition motif (RRM), the surface of which is
largely occluded by a C-terminal alpha-helix and a portion of the SF3b155
peptide. An analysis of RNA.protein crosslinking to wild-type and mutant p14
shows that the branch adenosine directly interacts with a conserved aromatic
within a pocket on the surface of the complex. This result, combined with a
comparison of the structure with known RRMs and pseudoRRMs as well as
model-building by using the electron cryomicroscopy structure of a spliceosomal
U11/U12 di-snRNP, suggests that p14.SF3b155 presents a noncanonical surface for
RNA recognition at the heart of the mammalian spliceosome.
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Figure 2.
Fig. 2. Details of p14·SF3b155 interface. (A)
Hydrophobic core of the p14·SF3b155 interface. p14 is
colored yellow, and SF3b155 peptide is colored blue. (B)
Hydrogen-bonding network and salt bridges surrounding the
hydrophobic core. p14 is colored yellow, and SF3b155 peptide is
colored blue. Hydrogen bonds involved in secondary structural
elements are omitted. (C) Surface representation of the
p14·SF3b155 complex showing Y22 of RNP2 exposed within a
surface pocket surrounded by conserved basic residues. p14 is
shaded light gray, SF3b is shaded dark gray, Y22 is colored
yellow, and R24, R57, R96, and K100 are colored blue.
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Figure 4.
Fig. 4. Comparison between p14·SF3b155 peptide
surface and structures of U1A and U2AF65 RRM3. (A)(Left) NMR
structure of free U1A with C-terminal helix (in yellow)
positioned across RNA-binding surface (19). (Middle) X-ray
structure of free U1A showing C-terminal helix rotated to unmask
the RNA binding surface (20). (Right) Structure of
p14·SF3b155 complex showing C-terminal helices of p14 and
Sf3b155 peptide (in yellow). RNP1 and RNP2 are colored red and
blue, respectively. (B) Representation of surface charges of
p14·SF3b155 and U2AF homology motif (RRM3) of U2AF^65.
The color scheme is as follows: blue, basic; red, acidic; white,
neutral.
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