The proposed research will provide new and comprehensive insight into debranching enzyme (Dbr1) that is a metalloenzyme central to the processing and biogenesis of regulatory RNAs. The use of modified branched RNA (bRNA) substrates and mimics will allow biochemical, structural and single-molecule studies into the binding, recognition and catalytic cleavage mechanism of Dbr1. This dissection of the molecular underpinnings of Dbr structure, function and dynamics is critical to the understanding of the unique specificity of Dbr1 and its active-site in cleavage of the bRNA 2'-5'-phophodiester cleaved. Through unprecedented access to synthetic bRNA, biochemical studies are proposed here to evaluate the active site residues and substrate requirements of Dbr1. Crystallographic analysis of Dbr1 will inform and enhance these biochemical studies by providing molecular details of protein and RNA contacts relevant to recognition, specificity and cleavage. Further, single-molecule spectroscopy will probe the dynamics of the macromolecular interactions to furnish important details into the reaction pathway and mechanism. The trifecta of methods proposed will provide a synergistic and cohesive account of the molecular details of Dbr1 cleavage of bRNA. These molecular details are critical for interventions through designed inhibitors in future therapeutic paradigms.

Public Health Relevance

RNA plays a central role in the proper cellular function and debranching enzyme is responsible for the generation of various critical RNA components. Thus, understanding the mechanism and functional properties of debranching enzyme will directly enhance the ability to design new interventions and therapeutic paradigms to control and address cellular function that affects human health.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM110414-02
Application #
8848405
Study Section
Macromolecular Structure and Function B Study Section (MSFB)
Program Officer
Preusch, Peter
Project Start
2014-06-01
Project End
2018-02-28
Budget Start
2015-03-01
Budget End
2016-02-29
Support Year
2
Fiscal Year
2015
Total Cost
$279,462
Indirect Cost
$89,462
Name
Carnegie-Mellon University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
052184116
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Ransey, Elizabeth; Paredes, Eduardo; Dey, Sourav K et al. (2017) Crystal structure of the Entamoeba histolytica RNA lariat debranching enzyme EhDbr1 reveals a catalytic Zn2+ /Mn2+ heterobinucleation. FEBS Lett 591:2003-2010
Mack, Stephanie; Fouz, Munira F; Dey, Sourav Kumar et al. (2016) Pseudo-Ligandless Click Chemistry for Oligonucleotide Conjugation. Curr Protoc Chem Biol 8:83-95