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PDBsum entry 3bap
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RNA binding protein
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PDB id
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3bap
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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 the 25 kda subunit of human cleavage factor im.
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Authors
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M.Coseno,
G.Martin,
C.Berger,
G.Gilmartin,
W.Keller,
S.Doublié.
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Ref.
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Nucleic Acids Res, 2008,
36,
3474-3483.
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PubMed id
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Abstract
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Cleavage factor I(m) is an essential component of the pre-messenger RNA 3'-end
processing machinery in higher eukaryotes, participating in both the
polyadenylation and cleavage steps. Cleavage factor I(m) is an oligomer composed
of a small 25 kDa subunit (CF I(m)25) and a variable larger subunit of either
59, 68 or 72 kDa. The small subunit also interacts with RNA, poly(A) polymerase,
and the nuclear poly(A)-binding protein. These protein-protein interactions are
thought to be facilitated by the Nudix domain of CF I(m)25, a hydrolase motif
with a characteristic alpha/beta/alpha fold and a conserved catalytic sequence
or Nudix box. We present here the crystal structures of human CF I(m)25 in its
free and diadenosine tetraphosphate (Ap(4)A) bound forms at 1.85 and 1.80 A,
respectively. CF I(m)25 crystallizes as a dimer and presents the classical Nudix
fold. Results from crystallographic and biochemical experiments suggest that CF
I(m)25 makes use of its Nudix fold to bind but not hydrolyze ATP and Ap(4)A. The
complex and apo protein structures provide insight into the active oligomeric
state of CF I(m) and suggest a possible role of nucleotide binding in either the
polyadenylation and/or cleavage steps of pre-messenger RNA 3'-end processing.
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