Frequency domain fluorometry: theory and application.

Frequency domain fluorometry is a widely utilized tool in the physical, chemical, and biological sciences. This chapter focuses on the theory of the method and the practical aspects required to carry out intensity decay, i.e.

Spectroscopic investigation of the noncovalent association of the nerve agent simulant diisopropyl methylphosphonate (DIMP) with zinc(II) porphyrins.

Organophosphonates pose a significant threat as chemical warfare agents, as well as environmental toxins in the form of pesticides. Thus, methodologies to sense and decontaminate these agents are of significant interest. Porphyrins and metalloporphyrins offer an excellent platform to develop chemical threat sensors and photochemical degradation systems.

Investigations of protein-protein interactions using time-resolved fluorescence and phasors.

Protein interactions are critical for biological specificity and techniques able to characterize these interactions are of fundamental importance in biochemistry and cell biology. Fluorescence methodologies have been extremely useful for studying many biological systems including protein-ligand and protein-protein interactions. In this review we focus on the application of time-resolved fluorescence approaches to macromolecular systems.

How can proteins enter the interior of a MOF? Investigation of cytochrome c translocation into a MOF consisting of mesoporous cages with microporous windows.

It has been demonstrated for the first time that the heme protein cytochrome c (Cyt c) can enter the interior of a MOF despite the larger molecular dimension of the protein relative to the access pore sizes. Mechanistic studies suggest that the Cyt c molecules must undergo a significant conformational change during translocation into the MOF interior through the relatively small nanopores.

Mimicking heme enzymes in the solid state: metal-organic materials with selectively encapsulated heme.

To carry out essential life processes, nature has had to evolve heme enzymes capable of synthesizing and manipulating complex molecules. These proteins perform a plethora of chemical reactions utilizing a single iron porphyrin active site embedded within an evolutionarily designed protein pocket. We herein report the first class of metal-organic materials (MOMs) that mimic heme enzymes in terms of both structure and reactivity.

Time resolved thermodynamics associated with ligand photorelease in heme peroxidases and globins: Open access channels versus gated ligand release.

Heme proteins represent a diverse class of biomolecules responsible for an extremely diverse array of physiological functions including electron transport, monooxygenation, ligand transport and storage, cellular signaling, respiration, etc. An intriguing aspect of these proteins is that such functional diversity is accomplished using a single type of heme macrocycle based upon iron protoporphyrin IX. The functional diversity originates from a delicate balance of inter-molecular interactions within the protein matrix together with well choreographed dynamics that modulate the heme electronic structure as well as ligand entry/exit pathways from the bulk solvent to the active site.

Excited state properties of 9-amino acridine surface adsorbed onto αZr-phosphate particles.

In this report the photo-physical properties of 9-amino acridine (9AA) associated with αZr-phosphate particles (αZrP) is examined. In ethanol solution 9AA exhibits absorption maxima at 425 nm, 402 nm and 383 nm as well as emission bands centered at 455 nm and 483 nm (using 423 nm excitation). The corresponding emission decay is monophasic with a lifetime of 16.