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Title: Crystal Structure of the 25 kDa Subunit of Human Cleavage Factor I{m}

Cleavage factor Im 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 Im is an oligomer composed of a small 25 kDa subunit (CF Im25) 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 Im25, 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 Im25 in its free and diadenosine tetraphosphate (Ap4A) bound forms at 1.85 and 1.80 Angstroms, respectively. CF Im25 crystallizes as a dimer and presents the classical Nudix fold. Results from crystallographic and biochemical experiments suggest that CF Im25 makes use of its Nudix fold to bind but not hydrolyze ATP and Ap4A. The complex and apo protein structures provide insight into the active oligomeric state of CF Im and suggest a possible role of nucleotide binding in either the polyadenylation and/or cleavage steps of pre-messenger RNA 3'-end processing.
Authors:
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Publication Date:
OSTI Identifier:
959942
Report Number(s):
BNL--82928-2009-JA
Journal ID: ISSN 0305-1048; NARHAD; TRN: US201016%%1086
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nucleic Acids Research; Journal Volume: 36; Journal Issue: 10
Research Org:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org:
Doe - Office Of Science
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CLEAVAGE; CRYSTAL STRUCTURE; DIMERS; HYDROLASES; MACHINERY; NUCLEOTIDES; PROCESSING; PROTEIN STRUCTURE; RNA national synchrotron light source