In 1953, Dr. Alexander Rich was working for future Nobel laureate Linus Pauling at the California Institute of Technology when Pauling shared the news that British scientists James Watson and Francis Crick had discovered the spiral structure of DNA, nature’s carrier of hereditary information.
“I remember going home that night wondering about what that molecule could look like,” Dr. Rich said in a 2006 interview recorded for the Cold Spring Harbor Laboratory Oral History Collection.
“I couldn’t sleep,” he added. “So I went back to the lab where there was a model room with molecular models. And I started building it.”
But it was not until 20 years later that Dr. Rich famously used X-ray technology to produce a clear representation of the double helix, which proved Watson and Crick’s DNA structure correct.
Dr. Rich, the William Thompson Sedgwick professor of biophysics in MIT’s biology department, where he had taught since 1958, died of pneumonia April 27 in Massachusetts General Hospital. He was 90, lived in Cambridge, and continued working at the Massachusetts Institute of Technology until being hospitalized two months before his death.
In 1979, Dr. Rich led a team of MIT researchers that found a different form of DNA that spiraled to the left. It was called left-handed DNA, or Z-DNA, because of its zigzag spine. “The DNA molecule is in an entirely novel form, a member of a new ‘family’ organized in a left-handed double-helical form,” Dr. Rich told the Globe in 1979. “It differs significantly from the right-handed double helix proposed by Watson and Crick 26 years ago.”
In recognition of Dr. Rich’s many achievements, President Bill Clinton awarded him the National Medal of Science, the nation’s highest scientific award, in 1995.
Dr. Rich’s contributions “are so important today, but taken for granted,” said Shuguang Zhang, the associate director of the Center for Biomedical Engineering at MIT.
Despite accomplishments that led to advances in genetics and biotechnology, and contributed to the fight against infectious diseases and cancer, Dr. Rich was “warm, wonderful, and open-minded,” said Zhang, who added that scientists and students “never had to make an appointment to see him. His door was open to everyone.”
For many years, Dr. Rich would return home from his MIT lab, dine with his family, fall asleep reading the news- paper, then awaken at 11 p.m. to head back to the lab.
“He never wanted to move us out of Cambridge, because he loved being able to go to the lab at all hours,” said his daughter Jessica Rich Sturley of New York City. “At 2 a.m., there would be all these scientists there, eating popcorn and working in this wonderfully charged atmosphere.”
Dr. Rich, who was known as Alex, was born in Hartford. His parents were Russian immigrants and his father “admonished my brother and me to get an education because, as he stressed, you can never lose the education, even though you may lose jobs or your possessions,” Dr. Rich wrote in “The Excitement of Discovery,” an autobiographical essay that the Annual Review of Biochemistry published in 2004.
The family moved to Springfield, where Dr. Rich attended Springfield Technical High School and worked overnight shifts as a machinist at the Springfield Armory. “He learned to use a very careful machining tool that cuts the grooves into rifles that make the bullets spin,” said his son Benjamin of Brookline. “That’s what he was doing at age 16.”
In the 2004 essay, Dr. Rich recalled working the 11 p.m. to 7 a.m. shift his entire senior year. “At age 17, it did not seem too difficult to keep to this schedule,” he wrote, “and I found that I could do some of my homework while running the machines, especially memorizing Milton’s poems.”
Dr. Rich enrolled at Harvard College and interrupted his studies to enlist in a Navy officers training program. During World War II, he worked at Portsmouth Naval Shipyard and was sent to medical school at Syracuse University.
Leaving the military in 1946, he returned to Harvard. He graduated with a bachelor’s degree in chemistry in 1947 and from Harvard Medical School in 1949. Soon after, he met Jane King aboard a ship bound for Europe, and they married at her parents’ home in Cambridge in 1952. They lived in Pasadena, Calif., when he worked at Caltech, and in Bethesda, Md., when he was a scientist at the National Institutes of Health, before settling in Cambridge to raise their four children.
Dr. Rich served on many boards and was a member of the National Academy of Sciences, the American Philosophical Society, the French Academy of Sciences, and the Russian Academy of Sciences. He wrote hundreds of articles and helped found the biotech companies Alkermes in Cambridge and Repligen in Waltham.
His son said that although the MIT lab involved “lots of bright people and lots of hard, hard science,” Dr. Rich cared about more than molecular biology. “He didn’t believe in a world that didn’t have room for things like art,” Benjamin said. “He felt science should be fun and people should view it in different ways.”
About 30 years ago, Dr. Rich asked Joe Davis, an artist and a fellow in MIT’s architecture department, to be his lab’s artist-in-residence, an unusual move at the time. Today, Davis is considered a leader in the bio-art movement.
Davis recalled that when Dr. Rich “invited me I said, ‘Really?’ And a lot of people in MIT biology were saying, ‘What is this? What is he doing?’ But Alex had a vision, and now art and biology has evolved into its own field. He was one of its founding fathers.”
Dr. Rich also was a proponent of nuclear disarmament, and during his career he worked with NASA on the Viking mission to Mars.
He collected fossils, his son said, and once managed to bring a “spectacular, 150-pound piece of petrified wood” onto an airplane and home to Cambridge, where it sat on the front porch.
“Those kind of stories were plentiful,” Benjamin said, “but his biggest thing was people. He collected friends.”
Dr. Rich’s daughter said he liked to fix things, rather than replace them, and that included a threadbare set of pajamas that he continuously repaired on a sewing machine. His pockets always held “a handful of rubber bands,” she said. “Plus a Swiss Army knife. And a pen.”
A service has been held for Dr. Rich who, in addition to his wife, daughter, and son leaves another son, Josiah, of Providence, another daughter, Rebecca of Boston, and seven grandchildren.
“My driving force has always been curiosity, and one of the intrinsic rewards of a life in science is the excitement of uncovering some aspect of nature,” Dr. Rich wrote in the 2004 autobiographical essay.Kathleen McKenna can be reached at email@example.com.