LEHNINGER PRINCIPLES OF BIOCHEMISTRY - VOLUME 1. THE FOUNDATIONS OF BIOCHEMISTRY: STRUCTURE AND CATALYSIS - 2011

About the Authors

David L. Nelson was born in Fairmont, Minnesota, USA. He received his B.S. in chemistry and biology from St. Olaf College in 1964 and completed his Ph.D. in biochemistry at Stanford University School of Medicine under the guidance of Arthur Kornberg. As a postdoctoral fellow at Harvard Medical School, he worked with Eugene P. Kennedy, who was one of Lehninger's first graduate students. Nelson has been on the faculty at the University of Wisconsin–Madison since 1971, becoming a professor of biochemistry in 1982; he currently serves as the director of the Center for Biology Education.

Nelson's research focuses on signal Transduction regulating ciliary motion and endocytosis in the protozoan Paramecium (with most of his work dedicated to determining The Role of Enzymes, particularly protein Kinases, in signal transduction). His research group employs modern experimental approaches, including various Protein Purification techniques, immunological assays, Electron Cell/15.html">Microscopy, as well as genetic, molecular biological, and electrophysiological Methods.

Nelson is widely recognized as an outstanding lecturer and educator. For over 40 years, he has directed biochemistry lecture courses for undergraduate students majoring in various biological sciences. He also teaches biochemistry to nursing students and graduate courses in membrane Structure and function and molecular neurophysiology. He has initiated numerous scholarship programs to support dedicated undergraduate and graduate students. For his exceptional teaching, Nelson has received numerous awards, including the Dreyfus Teacher-Scholar Award. He is an emeritus professor at the University of Wisconsin. In 1991–1992, he served as a visiting professor at Spelman College. The second passion of his life is The history of science; he teaches a course on the history of biochemistry to undergraduates and maintains a personal collection of antique scientific instruments.

Class="center">David L. Nelson and Michael M. Cox

Michael M. Cox was born in Wilmington, Delaware, USA. Early in his studies, Lehninger's textbook had such a profound impact on Cox that it redirected his scientific interests from biology to biochemistry. After graduating from the University of Delaware in 1974, Cox completed his Ph.D. at Brandeis University under the supervision of William P. Jencks; from 1979, he worked at Stanford University under Robert Lehman. Since 1983, Cox has been at the University of Wisconsin–Madison, where he has been a professor of biochemistry since 1992. His doctoral dissertation focused on applying the general Acid-Base Catalysis model to study enzymatic reactions. At Stanford, he investigated enzymes involved in genetic recombination, with a primary focus on the RecA protein and The Mechanism of DNA strand exchange; the METHODS FOR ISOLATION and Analysis of the RecA protein developed by Cox are still in use today. The central theme of his scientific career has always been The Study of enzymes involved in genetic recombination.

At the University of Wisconsin, Cox directs a large and active research group working in the fields of enzymology, topology, and the energetics of genetic recombination. The primary focus of his research team is the mechanisms of DNA strand exchange mediated by the RecA protein, the role of ATP in the RecA system, and The regulation of recombinational DNA Repair. Part of the group's work is dedicated to studying Deinococcus radiodurans Cells, which possess an extraordinarily robust repair system, and exploring biotechnological Applications of this repair machinery.

For over a quarter of a century, Cox has co-taught the undergraduate biochemistry course with D. Nelson and lectured graduate students on Introduction/20.html">DNA Structure AND topology, DNA-Protein Interactions, and the biochemistry of recombination. First-year graduate students take his course on the professional responsibilities of scientists. For his research and teaching, Cox received the Dreyfus Teacher-Scholar Award and the Eli Lilly Award in Biological Chemistry in 1989. His hobbies include gardening, wine collecting, and participating in the architectural planning of research facilities.

A Few Words About Science

At the dawn of the 21st century, classical science education often fails to give due attention to the philosophy of science and the foundational principles of scientific theories. Since you are likely pursuing a future in scientific research, it is fitting to pause here and re-examine the core meanings of such concepts as science, the scientist, and the scientific method.

Science is simultaneously a way of observing the natural world and the body of data and theories that emerge from those observations. The power and success of science stem directly from propositions that can be tested by investigating natural phenomena that are observable, measurable, and reproducible, or by proposing theories with predictive power. Scientific progress rests on a fundamental principle that is rarely discussed yet vitally important: the constancy of the laws governing forces and phenomena throughout the universe. Nobel laureate Jacques Monod referred to this principle as the "postulate of objectivity of nature." Thus, the world around us can be understood by applying the scientific method, much as it is done in scientific research. If the universe did not operate under strict laws, science could not successfully progress. Aside from the postulate of objectivity, science makes no assumptions about the surrounding world that are not subject to revision and refinement. Only those scientific ideas or hypotheses are acceptable that (1) are reproducibly confirmed and (2) can be used to accurately predict new phenomena.

Scientific ideas can take various forms, and the meanings of the terms used by scientists often differ significantly from how non-scientists understand them. For instance, a hypothesis is an idea or proposition that provides a reasonable and testable explanation for one or more observations, though it may lack extensive experimental backing. A scientific theory goes much further; it is an idea supported by a substantial body of experimental evidence that accounts for a broad range of related observations.

A scientific theory is always grounded in facts and is testable, allowing it to be applied in further research. When a scientific theory has been repeatedly tested against facts and verified across many parameters, it may come to be accepted as a scientific fact.

In short, scientific ideas form the content of research papers published in peer-reviewed scientific journals. Every year, roughly 1.4 million articles are published across 16,000 scientific journals worldwide, and this wealth of information is accessible to anyone.

Scientists are individuals who apply the scientific method to understand the world around them. One does not become a scientist simply by earning an academic degree or title, nor does the lack of such credentials prevent someone from making a profound contribution to science. A true scientist is driven to formulate hypotheses in response to new data. Accepted scientific hypotheses must be based on measurable and reproducible observations, and a scientist must report these observations with absolute honesty.

The scientific method encompasses a diverse set of research pathways, any of which can lead to scientific discovery. The hypothesis-to-experiment pathway involves a scientist formulating a hypothesis and testing it experimentally. Many biochemical processes that biochemists encounter in their daily work were discovered in this exact manner. James Watson and Francis Crick deduced The structure of DNA; this breakthrough led to the hypothesis that DNA base pairing underlies the transmission of Genetic information during polynucleotide synthesis, which in turn paved the way for the discovery of RNA and DNA polymerases.

Watson and Crick uncovered the DNA structure using modeling and calculation methods. They conducted no independent experiments of their own, instead utilizing experimental data previously gathered by other scientists. Some bold researchers have chosen observation as their primary scientific method. Discoveries made by renowned explorers—such as Charles Darwin during his voyage on HMS Beagle in 1831—helped map our planet, catalog its inhabitants, and fundamentally alter our perception of the world. Modern scientists exploring the ocean depths or launching probes to distant planets follow this very same path of inquiry. Another approach, closely related to the hypothesis-experiment pathway, is the hypothesis-deduction method. Crick reasoned that an intermediate molecule must exist to carry information from Messenger RNA to Proteins. This brilliant hypothesis led to Hoagland and Zamecnik's discovery of Transfer RNAs.

Not all scientific discoveries happen "according to plan"; an investigator's intuition (insight) often plays a crucial role. Alexander Fleming's discovery of penicillin in 1928 and Thomas Cech's Discovery of the catalytic activity of RNA in the early 1980s were, to some extent, fortunate accidents, yet these scientists were uniquely prepared to recognize and capitalize on their findings. Inspiration can play an equally vital role. For example, the Polymerase Chain Reaction (PCR)—now a cornerstone of biotechnological research—was conceived by Kary Mullis in a flash of inspiration while driving through Northern California in 1983.

While these pathways to scientific discovery may at first glance seem disparate, they share profound commonalities. All of them are aimed at exploring the natural world. All rely on reproducible observation and/or experimentation. All ideas and experimental evidence associated with scientific inquiry can be verified and replicated by researchers anywhere in the world. All scientific hypotheses and discoveries are available for other scientists to build upon in generating new hypotheses and making new breakthroughs. Above all, they generate information that continuously enriches the collective body of human scientific knowledge. Unraveling the workings of the universe is hard work, but there is no more exhilarating or worthwhile pursuit than striving to understand, even in part, how the world is put together.