8-Azapurines as isosteric purine fluorescent probes for nucleic acid and enzymatic research

2014 ◽  
Vol 10 (11) ◽  
pp. 2756-2774 ◽  
Author(s):  
Jacek Wierzchowski ◽  
Jan M. Antosiewicz ◽  
David Shugar

We review fluorescence emission properties of 8-azapurines and related compounds, and their potential as fluorescence probes in various biochemical systems.

Author(s):  
Howard M. Shapiro

In the jargon of cytometry, cellular characteristics, such as size, nucleic acid content, and membrane potential, are usually referred to as parameters, a term that is also used for the physical characteristics, such as absorption, light scattering, and fluorescence intensity, that are measured by cytometric instrumentation. Fluorescence, as a physical parameter, plays a key role in the detection of probes on beads for multiplexed analysis. Cellular parameters can be classed as intrinsic or extrinsic. Intrinsic cellular parameters are those that can be measured without the use of a reagent; measurement of extrinsic parameters requires the use of reagents, which are almost always referred to as probes, thereby occasioning confusion among molecular biologists new to cytometry. Cellular parameters are also characterized as structural or functional; DNA and RNA content and the presence and copy number of an antigen or nucleic acid sequence are structural parameters, whereas internal pH, membrane potential, and enzyme activity are functional parameters. The distinction between structural and functional parameters blurs at the edge, but the concept has been generally useful. Fluorescent probes allow measurement of the widest variety of extrinsic cellular parameters. For an atom or molecule to fluoresce, it must first absorb a photon, raising an electron to a higher energy level that is known as an excited state. Excitation by absorption requires only about a femtosecond. Fluorescence occurs when the electron loses all or some of the absorbed energy by emission of a photon. The fluorescence lifetime, that is, the period between excitation and emission, is typically on the order of a few nanoseconds for fluorescent organic materials but is notably longer (hundreds of microseconds) for some materials (e.g., lanthanide chelates). In almost all cases, some of the excitation energy is lost nonradiatively by transitions between different vibrational energy levels of the electronic excited state; this loss requires that the emitted energy be less than the energy absorbed, meaning that the fluorescence emission will be at a longer wavelength than the excitation. The difference between the principal excitation and emission maxima in the fluorescence spectrum is known as the Stokes shift, honoring George Stokes, who first described fluorescence in the mid-1800s. Typical Stokes shifts are no more than a few tens of nanometers.


1951 ◽  
Vol 189 (1) ◽  
pp. 151-157 ◽  
Author(s):  
Frederick J. Di Carlo ◽  
Alfred S. Schultz ◽  
Doris K. McManus

2010 ◽  
Vol 2010 (5) ◽  
pp. 278-282 ◽  
Author(s):  
Jian-Yong Hu ◽  
Hidetaka Hiyoshi ◽  
Jung-Hee Do ◽  
Takehiko Yamato

1983 ◽  
Vol 26 (5) ◽  
pp. 661-666 ◽  
Author(s):  
Erik De Clercq ◽  
Johan Descamps ◽  
Jan Balzarini ◽  
Jerzy Giziewicz ◽  
Philip J. Barr ◽  
...  

1973 ◽  
Vol 51 (9) ◽  
pp. 1313-1321 ◽  
Author(s):  
Morris J. Robins ◽  
James R. McCarthy Jr. ◽  
Roger A. Jones ◽  
Rudolf Mengel

Reaction of tubercidin (4-amino-7-β-D-ribofuranosylpyrrolo[2,3-d]pyrimidine) (1) with α-acetoxyisobutyryl chloride in the presence of excess sodium iodide in acetonitrile gave an acylated iodo intermediate (2) which was converted into 3′-deoxytubercidin (4) by hydrogenolysis and subsequent saponification.Analogous treatment of formycin (7-amino-3-β-D-ribofuranosylpyrazolo[4,3-d]pyrimidine) (5) gave 3′-deoxyformycin (6) and 2′-deoxyformycin (7) in an approximate ratio of 3:2. These purified nucleosides, 6 and 7 were individually deaminated enzymatically to give 3′-deoxyformycin B (8) and 2′-deoxyformycin B(9).Biological rationale, n.m.r., and mass spectra of these antibiotic-derived deoxynucleosides are discussed.


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