Abstract/Details

Design, synthesis, and evaluation of fluorescent small molecule probes of biological systems


2008 2008

Other formats: Order a copy

Abstract (summary)

Fluorescent derivatives of biologically active molecules are essential tools for studying molecular interactions at the cellular level. Fluorescent tags and/or labels have been used to study protein-protein interactions, intracellular localization of biomolecules and organelles, and small molecule-protein interactions. We report here studies of fluorescent ligands of Peroxisome Proliferator Activated Receptors (PPARs), protein targets under intense investigation for the treatment of human metabolic disorders. Such fluorescent ligands have the potential to enable faster identification of novel therapeutics. To pursue this goal, we synthesized a variety of fluorescent small molecule PPAR ligands for high-throughput examination of potential endogenous and exogenous ligands that bind these proteins. We found that our fluorescein labeled PPAR ligands bound PPARγ and PPARα with high selectivity and were good candidates for fluorescence polarization assays. In addition, we also utilized Pennsylvania Green as a more hydrophobic analogue of fluorescein to generate cell-permeable versions of these PPAR probes to develop a novel method for studying PPAR ligand binding in living cells, which can be further extended to other related members of the nuclear hormone receptor family.

To extend previously reported studies on 3β-cholesterylamine derivatives that function as non-natural cell surface receptors, we synthesized a series of Oregon Green labeled symmetrical dimers of 3β-cholesterylamine as potential precursors to membrane spanning artificial cell surface receptors. We examined these compounds using confocal microscopy, flow cytometry, and spectroscopy to identify the optimal structural requirements for insertion into membranes of living mammalian cells. Modeled after our best compound, we synthesized an asymmetrical 3β-cholesterylamine dimer bearing Oregon Green as an extracellular fluorescent label and biotin as an intracellular ligand of streptavidin expressed in the cytosol. Examination of this dimer using confocal microscopy showed low cellular association, which could be due to the non-protonatable amide bearing biotin. Further studies to generate synthetic analogues bearing protonatable groups on the intracellular motif could project biotin into the cytosol and recruit streptavidin to the inner-leaflet of the membrane. Through intracellular control of protein localization it is postulated that asymmetrical cholesterylamines of this type could be used to influence internal cell signaling and cellular uptake pathways. Artificial cell surface receptors that span cellular membranes could provide a new strategy for controlling therapeutically relevant intracellular pathways.

Indexing (details)


Subject
Cellular biology;
Biochemistry;
Organic chemistry;
Pharmacy sciences
Classification
0379: Cellular biology
0487: Biochemistry
0490: Organic chemistry
0491: Pharmacy sciences
Identifier / keyword
Pure sciences; Biological sciences; Biological probes; Cholesterol; Fluorescent; Membrane spanning; PPAR; Receptors; Small molecule
Title
Design, synthesis, and evaluation of fluorescent small molecule probes of biological systems
Author
DeGrazia, Michael James
Number of pages
232
Publication year
2008
Degree date
2008
School code
0176
Source
DAI-B 69/08, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780549769446
University/institution
The Pennsylvania State University
University location
United States -- Pennsylvania
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3325903
ProQuest document ID
304507208
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304507208
Access the complete full text

You can get the full text of this document if it is part of your institution's ProQuest subscription.

Try one of the following:

  • Connect to ProQuest through your library network and search for the document from there.
  • Request the document from your library.
  • Go to the ProQuest login page and enter a ProQuest or My Research username / password.