Crystallising the tobacco mosaic virus

June 29, 2015 05:43 pm | Updated November 10, 2021 12:32 pm IST

We saw last week how sulphur dioxide released from the Laki fissure system accounted for many deaths due to poisoning. We will stay with poisons this week as well, for virus has its roots in the Latin term for “poison”. We will look at Wendell Meredith Stanley, who reported the first virus in crystalline form on June 28, 1935.

Stanley was born on August 16, 1904 in Ridgeville, Indiana, United States, to parents, who were involved in the local newspaper business. He majored in chemistry and mathematics, but his interests were elsewhere. He was the captain of the college American football team and was also part of the Indiana all-state selection in his senior year. After receiving his B.S. in 1926, it was no surprise that he wanted to become an athletics coach.

It was at this time that he met Roger Adams, who was head of the Chemistry department at the University of Illinois, Champaign-Urbana. Adams changed Stanley’s mind and as a result he began his undergraduate work under Adams before going on to complete his M.S. in 1927 and Ph.D. in 1929.

He became an assistant at the Rockefeller Institute for Medical Research and by 1932 had been transferred to the Department of Plant and Animal Pathology to work on tobacco mosaic virus (TMV). TMV, which was already well known to laboratory researchers, caused spots on leaves that were infected with it. It had already been shown that TMV could be manipulated chemically without it losing its ability to infect.

As a trained chemist, Stanley differed in his perspectives when compared to those of microbiologists. He decided to apply biochemical techniques for crystallisation that had been recently developed by his Rockefeller colleagues to the TMV. And in 1935, Stanley was successful in crystallising TMV and thereby described its molecular structure.

Tobacco mosaic virus was the first virus to be crystallized. The virus causes mosaic diseases in tobacco. The process of transforming the components of a virus into organised particles and thereby describing their molecular structure using X-Ray crystallography technique is called crystallisation. This enables one to study the characteristics of a virus.

Stanley continued to study virology for much of his career and worked to promote public health care throughout his life. He won the 1946 Nobel Prize in Chemistry along with John Howard Northrop and James Batcheller Sumner. While Sumner won it for “his discovery that enzymes can be crystallised”, Northrop and Stanley shared it for “their preparation of enzymes and virus proteins in a pure form.”

Nature of viruses, however, continues to be a mystery to this day. It was first thought to be a form of poison (and hence its name), then a life-form and then as biological chemicals. We now know that viruses cannot replicate on their own, but can do so in living cells, also with the ability of affecting the host’s behaviour completely.

This has led to the current understanding that classifies viruses as being somewhere between living and nonliving. This has also allowed scientists to see that viruses might indeed have a more fundamental role in the history of life.

Reach A.S.Ganesh at

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