Alexander Rich, 1924-2015

Alexander Rich. Photo by Donna Coveney.

Alexander Rich. Photo by Donna Coveney.

Today we remember Dr. Alexander Rich, a student and colleague of Linus Pauling who passed away in April at the age of 90. Rich and Pauling were among the group of scientists who embarked on one of the most exciting scientific quests of the 20th century – the so-called “race for DNA.” Rich’s friends and colleagues also remember him for his endless desire to know more about the processes propelling life, a trait that is evident in his career as a biochemist. According to Pauling, this holistic interest in and understanding of science allowed Rich to make invaluable contributions to multiple disciplines.

Nucleic acids – the carriers of genetic information within a cell’s nucleus – were first identified in 1868 when Friedrich Miescher isolated the DNA compound for the first time. For some eighty-five years, however, the structure of DNA remained undescribed. In the 1940s and 1950s, scientists around the world began to focus more on the problem, working to build an accurate model of the DNA molecule in hopes of fully understanding its role in the process of gene expression.

In 1953, using Rosalind Franklin’s experimental data, James Watson and Francis Crick published their proposal of a double helical structure for the DNA molecule, and quickly became scientific celebrities once their model was deemed correct. Like Rosalind Franklin and, indeed, Linus Pauling, Alexander Rich was among the many researchers whose work and contributions to the understanding of proteins and nucleic acids abetted Watson and Crick’s discovery of the DNA molecule’s structure.


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Born in Hartford, Connecticut in 1924, Alexander Rich served in the U.S. Navy during World War II, then went on to Harvard University, where he received a bachelor’s degree in biochemical sciences in 1947 and graduated from Harvard Medical School in 1949. Soon after receiving his medical degree, he moved to Pasadena, where he worked as a research fellow in Linus Pauling’s lab at the California Institute of Technology, and where he lived with future Nobel laureate Martin Karplus, a fellow student of Pauling’s.

Blessed with a nimble mind, Rich was able to jump back and forth between chemistry and biology as his research interests progressed, all the while paying close attention to the broader implications of his research for the field of medicine. Rich became particularly well-known for his work on the structure and chemistry of fiber compounds, research which quickly became useful to the study of nucleic acids. By isolating strands of nucleic acids within fibrous compounds, Rich was able to produce images of their structure.

Though his pictures were not as clear or impactful as those captured by Rosalind Franklin, many have since posited that his work could have been of equal significance to Franklin’s had Caltech housed more fine-focus x-ray equipment.  Regardless, Rich was held in high esteem by Watson and Crick who, before publishing their DNA structure, asked that Rich review their work and corroborate their ideas.

Collagen model built by Alexander Rich and Francis Crick. September 1955.

In the wake of Watson and Crick’s triumph, the structure of nucleic acids continued to intrigue Rich. This time around however, it was RNA that caught his attention. Like DNA, RNA carries genetic material and is vital to the formation of proteins. It is thus necessary to understand the structure and function of RNA to fully comprehend DNA’s role in protein formation.

Rich began research in this area during James Watson’s brief stay at Caltech, and some now speculate that Rich’s interest in RNA images led Watson to focus entirely on RNA. While in Pasadena, Rich and Watson collected different images of RNA in an attempt to understand its physical structure, but the x-ray crystallographic photographs available at the time were not sufficient enough to discern a conclusive model.

Rich’s stint at Caltech came to an end in 1954 and he subsequently moved into his own laboratory at the National Institute of Mental Health (NIMH). While there he continued to delve into questions regarding the structure and composition of RNA. At the NIMH Rich was, at long last, successful in creating an image of RNA that provided hints about its structure. Rich concluded that RNA consists of a single-stranded nucleic acid that binds with complementary strands of RNA to form a temporary double helix – a process he described as molecular hybridization. Many were skeptical that a single-stranded nucleic acid could temporarily form a double helix, but Rich was able to show that this is made possible by the shedding of water molecules that comes about when the two strands bind.

Not only did this finding contribute enormously to the understanding of RNA’s structure and function, but Rich’s contributions to the understanding of molecular hybridization in nucleic acids has opened up many more possibilities. For example, polymerase chain reaction, a process used to identify genes, is based on the principle of hybridization. Today, methods of this sort are fundamental to all sorts of work in biotechnology and to the analysis of DNA.

Alexander Rich with Linus Pauling, among others, at a scientific meeting in the Soviet Union.  Image Source: Alexander Rich Collection.

Alexander Rich with Linus Pauling, among others, at a scientific meeting in the Soviet Union. Image Source: Alexander Rich Collection.

Following his tenure at the NIMH, Rich became a professor of Biophysics at the Massachusetts Institute of Technology, beginning in 1958 and lasting until his death. His investigations there included the discovery of Z-DNA, which is a type of DNA molecule that takes a zigzag form and follows a left-handed wind rather than the more common right-handed wind. His work at MIT also showed that protein synthesis occurs in a polysome – the name given to a cluster of Ribosomes that work together.

Alexander Rich received high honors for his contributions, including election to the National Academy of Sciences and receipt of the 1995 National Medal of Science – the highest scientific honor bestowed by the U.S. government.  It is no wonder then that Linus Pauling recalled his former pupil with great pride. “Of the several men with MD degrees who have worked with me,” he once noted, “I think that Dr. Rich may well be the one with the broadest grasp of science as a whole.”

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