Luciferases and Fluorescent Proteins: Principles and Advances in Biotechnology and Bioimaging 2007

From the Preface
Bioluminescence, the emission of visible light by living organisms, has called the attention of many scientists for many centuries. It poses many fundamental questions about the conversion of energy and exchange of information in biological systems. During the first half of the 20th century, the biochemical basis of bioluminescent systems was established. Studies by Harvey and others showed that most bioluminescent organisms use a thermostable oxidazible compound called luciferin, an enzyme called luciferase and oxygen. During the second half of 20 century, considerable progress was made in understanding the details of many bioluminescent systems, mainly those from bacteria, algae, coelenterates, crustaceans and beetles. Several luciferin, luciferases and accessory fluorescent proteins were isolated and characterized. Currently, three kinds of proteins are involved in light generation in bioluminescent organisms: (1) luciferases, the enzymes that catalyze the luciferin oxidation, generating a primary excited product that can be the actual emitter; (2) photoproteins, a special case of luciferase, in which a temporarily stable protein-lumophore is the actual emitter and (3) fluorescent proteins, proteins with an endogenous fluorophore that serve as excitation energy acceptors from the primary light-generating reaction (luciferase or photoprotein), emitting at a different wavelength. Some of these systems promptly became used for bioanalytical purposes, for instance, bacterial luciferase as an oxygen probe, coelenterate photoproteins as calcium indicators and firefly luciferase as ATP indicator. With the advent of molecular biology, many luciferase genes were cloned, and their DNA has been successfully introduced in all kind of cells as reporter genes for a variety of applications. The protein sequences of luciferases and fluorescent proteins were deduced and the structure/function relationships begun to be elucidated through genetic engineering. Furthermore, the three-dimensional structure of some luciferases, photoproteins and fluorescent proteins, became available and the number of studies keep increasing, giving important clues on how such unique proteins catalyze the production light and modulate bioluminescencence colors. Such information is giving important clues on how structure affects the function in proteins and how such relationship evolved during evolution, aiding different fields such as structural biology, enzymology, molecular evolution, and constituting didactic themes for teaching biochemistry, molecular biology, biophysics, genetics and evolution. On the other hand, such building knowledge is providing useful information to engineer the structure of these proteins in order to optimize their properties for biotechnological and biomedical purposes. These luminescent proteins are currently used as bioanalytical reagents and as reporter genes in a variety of applied fields. A new field of bioimaging is developing fast due to the use of these proteins as luminescent markers to probe living organisms in real time.
In the first part of this book, the structure/function relationship and molecular evolution of luciferases is provided. S.C. Tu will introduce the strucutre and function relationship of bacterial luciferases. E. Vijovsky and J. Lee will introduce coelenterate photoproteins. Aequorin luciferase will be presented by B. Lambolez and L. Tricoire. Ostracod luciferase will be introduced by C. Wu and Y.Ohmiya. Finally, I will introduce beetle luciferases.
In the second part of this book, fluorescent proteins will be assessed. S. Deo et al. will introduce red fluorescent proteins, an evolution of the classical green fluorescent proteins. Dr. H. Karatani will introduce bacterial blue and yellow fluorescent proteins.