skip to main content


Title: Crystal structure of the Entamoeba histolytica RNA lariat debranching enzyme EhDbr1 reveals a catalytic Zn 2+/Mn 2+ heterobinucleation

Here, the RNA lariat debranching enzyme, Dbr1, is a metallophosphoesterase that cleaves 2'-5' phosphodiester bonds within intronic lariats. Previous reports have indicated that Dbr1 enzymatic activity is supported by diverse metal ions including Ni 2+, Mn 2+, Mg 2+, Fe 2+, and Zn 2+. While in initial structures of the Entamoeba histolytica Dbr1 only one of the two catalytic metal-binding sites were observed to be occupied (with a Mn 2+ ion), recent structures determined a Zn 2+/Fe 2+ heterobinucleation. We solved a high-resolution X-ray crystal structure (1.8 Å) of the E. histolytica Dbr1 and determined a Zn 2+/Mn 2+ occupancy. ICP-AES corroborate this finding, and in vitro debranching assays with fluorescently labeled branched substrates confirm activity.
 [1] ;  [2] ;  [2] ;  [2] ;  [3] ;  [4]
  1. Harvard Medical School, Boston, MA (United States)
  2. Carnegie Mellon Univ., Pittsburgh, PA (United States)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. Butler Univ., Indianapolis, IN (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0014-5793
Grant/Contract Number:
Accepted Manuscript
Journal Name:
FEBS Letters
Additional Journal Information:
Journal Volume: 591; Journal Issue: 13; Journal ID: ISSN 0014-5793
Federation of European Biochemical Societies
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE; heterobinucleation; ICP-AES; metallophosphoesterase
OSTI Identifier: