Biomedical Engineering Reference
In-Depth Information
10
Biomarkers and Luminescent Probes
in Quantitative Biology
M. Zamai, G. Malengo, and V.R. Caiolfa
The genome sequence of many organisms is now complete. “However, genome
sequences alone lack spatial and temporal information and are therefore as
dynamic and informative as census lists or telephone directories” [1]. We know
the words of the genetic code, yet we need to associate each of them to a
specific function. The challenge of this century is to figure out how proteins
work together to make living cells and organisms. Proteins are essential for
most biological processes, but they are not simply objects with chemically
reactive surfaces, and it is not easy to understand their function. Proteins
localize to specific environments in the cells: membranes, cytosol, organelles,
or nucleoplasm, undergo diffusive or directed movement, and often are coupled
to chemical events. The exceptional capability of the proteins to regulate
virtually all dynamic processes in living cells depends on the fine regulation
of their topology, movement, and chemistry. In fact, cells respond to stimuli
through signaling pathways that orchestrate the recruitment and assembly
of proteins into biomolecular
machines
. Roadmap
1
focuses on ways to solve
the structures of protein machines. To achieve these goals, it is critical to
understand how the cell architecture influences the formation of these protein
complexes. Research is, therefore, turning to the study of protein function in
their most natural context [2].
10.1 Fluorophores and Genetic Dyes
10.1.1 Small Organic Dyes and Quantum Dots
Small organic fluorophores (
<
1 kDa) for covalent labeling of macromolecules
have been optimized for wavelength range, brightness (extinction coe
cient
for absorbance, fluorescence quantum yield) photostability, and reduction in
self-quenching. Hundreds of such dyes are commercially available [3]. However,
1
(http://www.nihroadmap.nih.gov)
