Effects of terbium chelate structure on dipicolinate ligation and the detection of Bacillus spores.

Abstract

Terbium-sensitized luminescence and its applicability towards the detection of Bacillus spores such as anthrax are of significant interest to research in biodefense and medical diagnostics. Accordingly, we have measured the effects of terbium chelation upon the parameters associated with dipicolinate ligation and spore detection. Namely, the dissociation constants, intrinsic brightness, luminescent lifetimes, and biological stabilities for several Tb(chelate)(dipicolinate)(x) complexes were determined using linear, cyclic, and aromatic chelators of differing structure and coordination number. This included the chelator array of NTA, BisTris, EGTA, EDTA, BAPTA, DO2A, DTPA, DO3A, and DOTA (respectively, 2,2',2″-nitrilotriacetic acid; 2,2-bis(hydroxymethyl)-2,2',2″-nitrilotriethanol; ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid; ethylenediamine-N,N,N',N'-tetraacetic acid; 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid; diethylenetriamine-N,N,N',N″,N″-pentaacetic acid; 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid; and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). Our study has revealed that the thermodynamic and temporal emission stabilities of the Tb(chelate)(dipicolinate)(x) complexes are directly related to chelate rigidity and a ligand stoichiometry of x=1, and that chelators possessing either aromaticity or low coordination numbers are destabilizing to the complexes when in extracts of an extremotolerant Bacillus spore. Together, our results demonstrate that both Tb(EDTA) and Tb(DO2A) are chemically and biochemically stable and thus applicable as respectively low and high-cost luminescent reporters for spore detection, and thereby of significance to institutions with developing biodefense programs.

• Authors: L S Barnes, K R Kaneshige, J S Strong, K Tan, H F von Bremen, R Mogul
• Journal: Journal of inorganic biochemistry (J Inorg Biochem) Vol. 105 Issue 12 Pg. 1580-8 (Dec 2011) ISSN: 1873-3344 [Electronic] United States
• PMID: 22071082 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
• Copyright: Copyright © 2011 Elsevier Inc. All rights reserved.

Chemical References

• Chelating Agents
• Coordination Complexes
• Indicators and Reagents
• Luminescent Agents
• Picolinic Acids
• Terbium
• dipicolinic acid

Topics

• Bacillus (physiology)
• Chelating Agents (chemistry)
• Coordination Complexes (chemical synthesis, chemistry)
• Indicators and Reagents (chemical synthesis, chemistry)
• Kinetics
• Luminescent Agents (chemical synthesis, chemistry)
• Picolinic Acids (chemistry)
• Regression Analysis
• Spores, Bacterial
• Structure-Activity Relationship
• Terbium (chemistry)
• Titrimetry