RIP Professor Sir Aaron Klug, OM.

RIP Professor Sir Aaron Klug, OM.

Radical Cambridge scientist and gifted theorist who won the Nobel prize in chemistry in 1982 for his work on the structures of viruses, passed away on 20 November, at the age of 92 years old.

In March 1954 Aaron Klug, then a young postdoctoral fellow at Birkbeck College, bumped into another researcher on the stairs outside their adjoining offices. They were both working in a cramped office in Bloomsbury, London, as part of a new biomolecular research laboratory.

A Lithuanian Jew who had grown up in South Africa and married a dancer, Klug was an unusual figure in the rather starchy, English circles of the University of London. More than that, he was extremely good at putting people at their ease. Many years later a friend would say that if you visited their colleague Francis Crick with a new idea, “you left the office quite sure that the idea had been his”. But if you visited Klug with no ideas at all, “you left the office quite sure that his new idea was yours”.

This was all, as it turned out, convenient, because the scientist Klug met on the stairs was the brilliant but difficult Rosalind Franklin. She had joined Birkbeck partly in search of a more cosmopolitan atmosphere after moving from Paris to King’s College London, which she had found narrow and constricting. And she was not naturally inclined to be trusting, perhaps understandably; her contribution to the discovery of the shape of DNA’s double helix was overlooked, and she had fallen out with Crick and James Watson the year before. Yet somehow, on that narrow staircase in a Georgian townhouse, she felt able to share the problem she was working on with Klug.

The meeting came at a good moment for Klug; he had just been sidelined by his lab boss in the search for the molecular shape of ribonuclease, and so was without a project. He was a naturally curious man, and found the x-ray crystallography images of viruses that Franklin showed him fascinating. This technique, involving diffracting x-rays through crystals of a substance, can show the shape of molecules, far too small to see with microscopes. But Franklin’s problem was that the light diffracting through the tobacco mosaic virus (TMV) appeared to be curved. That made no sense at all, according to theory, and Franklin was unable to interpret the shape.

Klug, who had studied x-ray crystallography for his PhD in Cape Town, was able to help out. He established that it was a perfect helix, but that the curve on the helix could not be expressed as a ratio of whole numbers, which accounted for the odd lines. He found himself enraptured by the intellectual challenge. At that moment on the stairs, he would later write, “My fate was sealed”.

For the next few years, until Franklin’s career and then her life were cut short by an aggressive ovarian cancer, the two scientists — Franklin the consummate experimentalist, Klug the gifted theorist — made a formidable team. Their work resulted in the first real progress in research on TMV since the late 1930s. Perhaps more importantly, it set Klug on the course that would win him the Nobel prize in chemistry nearly 30 years later. He would later describe Franklin as his scientific “mother”.

Aaron Klug was born in 1926 in Zelva, Lithuania, the son of Lazar Klug, a saddler, cattle-herder and occasional journalist, and Bella (née Silin), the daughter of a local shopkeeper. A Jewish family who spoke Yiddish at home, they found life in the Soviet empire was becoming increasingly difficult; more urgently, Lazar had killed a Red Army soldier while defending his brother’s life, and only narrowly avoided being shot. So when Aaron was two, the Klugs fled Lithuania for Durban, South Africa.

His childhood was in many ways stereotypically English. Durban ran itself along very Victorian lines, and Durban High School, where he was educated, was a place of woollen trousers and cricket. In deference to the local climate, the boys were allowed to remove their blazers if the temperature rose above 85F (30C). In other ways, though, it was African because the school was on the edge of the bush. Aaron had to dodge poisonous snakes on his bicycle, and on occasion defend his lunchbag from marauding troops of vervet monkeys.

He was a bright child — family legend has it that, despite speaking Yiddish to the age of two, he had taught himself to read English newspapers by the age of three and a half — and bookish; he would read about the renaissance popes, or hieroglyphics at Durban’s public library. His intellectual curiosity was fierce; throughout his life he would become fascinated by a topic, and rarely move on until he felt he had mastered it. Then he read Microbe Hunters by Paul de Kruif, and became enthralled by microbiology.

In 1941 he won, at the age of just 15, a scholarship to the University of Witwatersrand in Johannesburg, to do medicine, which seemed the best route to the study of microscopic life. However, he found it unsatisfying. Slowly he left medicine and built his own course, doing three majors, in maths, physics and chemistry, rather than the more usual one. He achieved a first-class degree.

After university he wanted to learn more about physics, so he went to Cape Town to do a master’s and then undertook research on x-ray analysis of compounds. He developed a new method for analysing the 3D shape of crystals from two-dimensional images.

In 1944, still only 18, he met the woman who would be his wife, Liebe Bobrow; she was two years younger, a dancer and musician, the daughter of a left-wing analytical chemist. Her family was quite upper-crust, a stark contrast from his more earthy roots. They became an item two years later, and married when he was 21, she 19. As a rebellious pair with rebellious friends who wanted to kick against the rather conventional, Victorian attitudes of South Africa at the time, they were a couple in a rush.

Specifically, they were supporters of the incipient Jewish state in Israel, which at the time was still the British mandate of Palestine, and to go there you needed a certificate. If you were married, two people could go on one certificate. They made several visits, but their involvement with teenage radicals had consequences: the South African government considered them communists, and would label Klug as such. This prevented him from travelling to the United States unless he signed a waiver saying that he had renounced his communist beliefs. Since he had had no such beliefs (he considered it insulting; “I was never prejudiced enough to be a communist,” Krug would say, although he was left of centre) he refused to do so. Later, when his fame had grown, the American government relented.

In 1949 he won a scholarship to do a PhD at Trinity College, Cambridge. After two weeks on a boat the Klugs arrived in a grey, wet London still scarred by bombs and rationing, and got the train to Cambridge. His topic of research was a theoretical problem on the cooling of steel; in the process he learnt enough metallurgy to understand the physical basis of the problem, as well as getting a grounding in computing and solid state physics. He also spent a year at Cambridge’s Colloid Centre.

After this he was awarded a Nuffield grant to work at Birkbeck. He did not see eye to eye with his boss there, and it was not until the chance meeting with Franklin that his career took off.

Liebe gave birth to their first son, Adam, in 1954; their second, David, would follow nine years later. Academia paid even less then than it does now, with Aaron earning just £350 a year (about £9,150 today), and they could only afford to live in a broken-down two-bed flat in Primrose Hill, which became a sort of halfway house for a series of South African Jewish émigrés. More often than not there would be people sitting on the carpet because there were never enough chairs.

At about this time, Franklin and Klug, fearful that Birkbeck had no place for them, asked Cambridge if they could work at the Medical Research Council-funded molecular biology lab that was being built at the university. Franklin did not live to see it, but Aaron and two of his graduate students established themselves there when it opened in 1962.

It was here that Klug did his most famous work during a period when his colleagues included many of the greatest scientists of the era: among them Francis Crick, John Kendrew, Fred Sanger and Hugh Huxley.

Klug brought together a group of biochemists, chemists and physicists who threw all their energies into the solution of the structure and assembly of complexes of nucleic acids and proteins that occur in viruses and in the nuclei of cells, using x-ray crystallography and electron microscopy. He transformed electron microscopy from a qualitative science into a quantitative one — a tool that allowed him and his colleagues to unravel the structures of many important viruses, including the general outline of the structure of the tobacco mosaic virus. Their final triumph was the structure of chromatin, the complex of nucleic acids that make up chromosomes.

In 1986 he became director of the laboratory. As a lab boss, he was solicitous of junior colleagues, and notably progressive, hiring many female scientists, as befitted someone who worked so closely with Rosalind Franklin, and allowing them to build their hours around childcare when needed.

Although Judaism was important to him, and he took his family to synagogue, he was never bound by the tradition in his own life, but loved it in the religious setting. Once, while on the phone to a lifelong friend, the Jewish South African author Dan Jacobson, they discussed whether they actually believed in God. Probably not, really, was the conclusion.

His work in Cambridge brought him the Nobel in 1982, and a knighthood in 1988. He had been made a fellow of the Royal Society in 1969, and became its president from 1995 to 2000. He was appointed in 1995 to the Order of Merit (OM), which recognises distinguished service in the armed forces, science, art, literature, or for the promotion of culture.

He helped to create the Sanger Institute, the genomics research laboratory in Cambridge that recently celebrated its 25th anniversary, and was influential behind the scenes in the Human Genome Project; there are not many significant biomedical projects that took place in the second half of the 20th century in which Klug was not at least tangentially involved.

Despite this, though, he was not keen to be pigeonholed as a “scientist”. He was a family man, and family conversations would be about politics, history, literature, not science. Both his sons followed him into academia, Adam in economics, David as a professor of chemistry. Adam died of cancer in 2000, aged 46. David and Liebe survive him.

Klug took on public-facing roles when he felt he had to, but, self-effacing as ever, he preferred to work behind the scenes, undertaking research or advising younger scientists.

His interest in topics outside science never left him. After his retirement, while taking a train to London to be appointed OM by the Queen, he saw a man reading a book about the history of Rome. “That’s what I’d really liked to have done,” he said, wistfully. Liebe patted him on the shoulder and said: “Well, it’s a bit late now.”


Candice Herbst