Chemosensing strategies : utilizing the novel sulfonamidohydroxyquinoline amino acid Sox

Modular peptide-based fluorescent chemosensors utilizing the chelation-sensitive fluorophore 8-hydroxy-5-(N,N-dimethylsulfonamido)-2-methylquinoline are powerful tools for sensing Zn²⁺ and for sensing protein kinase activity. This signaling component is prepared as the protected amino acid derivative Fmoc-Sox-OH, and integrated into peptide sequences. Selective and tunable chemosensors for Zn²⁺ can afford qualitative and quantitative information about the presence, distribution and concentration of this biologically-important metal ion. Nineteen synthetic peptides incorporating Sox exhibit a range of affinities for Zn²⁺ through variation of the type and number of Zn²⁺ ligands, ligand arrangement and the [beta]-turn sequence that acts as a preorganization element between the ligands. The binding stoichiometry and fluorescence response to pH changes and various relevant competing metal ions was carefully characterized. Eleven of these sequences form only 1:1 complexes with Zn²⁺ and their affinities range from 10 nM to nearly 1 [mu]M. When used in concert, the relative intensities of different chemosensor readouts can provide Zn²⁺ concentration information in a valuable range. This modular scaffold is useful for ratiometric sensing when an additional fluorophore is incorporated in the peptide sequence. New methods to quantify protein kinase activities are critical for understanding biological regulatory pathways. Fluorescent chemosensors of protein kinase activity utilizing Sox and physiological Mg²⁺ concentrations report phosphorylation with dramatic fluorescence changes in a continuous, high-throughput sensing format.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Shults, Melissa Dawn

Advisor dc:contributor.advisor

• Barbara Imperiali.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/32428

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/32428