Born in Lithuania in 1926, Aaron Klug is a British chemist and biophysicist, was awarded the Nobel Prize in Chemistry in 1982 for developments in electron microscopy and his work on complexes of nucleic acids and proteins. He studied crystallography at the University of Cape Town before moving to England, completing his doctorate in 1953 at Trinity College, Cambridge. In 1981, he was awarded the Louisa Gross Horwitz Prize from Columbia University. His long and influential career led to a knighthood in 1988. He was also elected President of the Royal Society, and served there from 1995-2000.
I got the scholarship to Cape Town where there was a professor of physics there, R.W.James, and I was taken on to do an MSc in Physics. It was because there was Â£20 a month; it was a lot of money in those days, in return for doing the MSc and also demonstrating in physics classes. But, because I hadn't learnt much physics at Wits, notwithstanding I had a degree, I went to all the second and third year lectures- things like system mechanics is really quite, quite advanced. James had been- R.W.James, very lucky to find him, I didn't know who he was, but he was the professor of physics and he'd been a colleague of Bragg- Lawrence Bragg, who created X-ray crystallography. And, he'd come out to Cape Town in 1937, I think in those days people would go to Cape Town or Melbourne and so on, it's all part of the cycle of- you might go to Cape Town, that was as far away as you might take Professorship in Nottingham or something like that, it was all part of the- what with the Commonwealth. It wasn't called the Commonwealth then it was called the- it was called the Dominion, basically it was the Commonwealth arrangement. So- so, from James, who was an excellent lecturer, excellent, and I- he taught a great deal of optics and I learnt a good deal of optics which again later stood me in good stead. But, there was a lot of things like birefringence ellipsoids and things of that sort; and, they were good experiments which I enjoyed.
Did the MSc involve research?
Yes, it involved research. It was supposed to be a- it was either a two-year course, mostly they did it in two, I did it in one year so my research was in X-ray crystallography. James had set up some- and, he- they were working on structures of organic compounds but the main line was to work on molecular complexes. And, there were some interesting problems but they were really the people really involved in that. Where you get two molecular- two molecules which don't interact but they crystallise together and there's quite a lot of- often they're quite incommensurate. So, you get extra spots in the diffraction patterns, some quite interesting bits of geometry how they line up. But, I was given the problem of para-chlorobromobenzene a very simple molecule, which somebody had crystallised and had reported rather strange things because it looked as though, the space lattice was indeterminate. So, I was given that as my MSc thesis; it was great fun because the X-ray sets were pretty primitive; there was a- there were- X-ray tubes were bought but the voltage, 40,000 volts were homemade. And, I- what you had to do was to set the voltage you had two spheres and you moved them together until you got a spark. And, you measure the rate of humidity and, from that- from the tables you could work the voltage. And it was- there was no such thing as safety devices but the windows were always kept shut and I said why? Because one of my predecessor had touched one of the spheres and was thrown across the room and nearly broke the window and would have fallen out, which is on the second floor, so it was there. But, I- so, I did that for my MSc and solved the structure of- and it turned out to be a structure in which the molecules para-chloro bromochlorine at one end of a benzene ring and bromine at the other and so they sat. They could sit in random rot- random orientation and, so, I- it was a bit of a surprise in those days, but, it got published in "Nature" in 1947, it was my first publication.
James gave lectures in crystallography?
No, that was- you learnt at the MSc course. The MSc course was mostly electromagnetism, relativity, wave mechanics not much quantum mechanics. But, during that year I attended- later on I attended lectures in applied maths where there was- that's where there was some Hamiltonian dynamics and a bit of quantum theory and so on. So, I always went to lectures, I always attended lectures. The- and, then I- and then they were introducing PhDs in Cape Town at the time and, so James said, why don't you stay on and do a PhD? So, I did a PhD, rather I started it and I worked on the structure of a molecule called triphenylene, an organic- rather. It's four benzene rings fused together, one in the middle and three on alternate sides of the middle benzene ring. I don't know what the interest was, but it was the- I should say the parachlorobromobenzene was pretty tricky to handle because it evaporated all the time and I had put it- I actually discovered how to keep it I- They didn't have glass capillaries at the time and what I did was to get hold of a- capsules that you get pills in, plastic capsules; you had to have something which would keep the vapour pressure. And so, I mounted them in these things and James thought it was very ingenuous, you know, because I could get X-ray pictures. So, that was- I forgot the point of it all, people weren't able to get decent pictures of para-chlorobromobenzene so I- I, I managed to do it. So, it proved, it didn't evaporate under vapour pressure, so it proved I could actually do something experimental though I'm often regarded as a theoretician. So, then, going back to tryphenyline doing this PhD, I had a grant, a small grant and the- I actually introduced a new method of trying to solve the crystal structures which was to calculate what are called molecular structure factors and Fourier transforms. And, by- by calculating the Fourier transforms, all done by hand, of course, on Beevers-Lipson strips, I calculated the Fourier transform of one molecule and then I worked out the possible positions in the lattice and that changes the interference function. It changes the sampling of the molecular transform; and, that was new, nobody had done that before. And, actually I didn't get the structure right, it was out by- it was so powerful, but I got the orientation absolutely right which accounted for most things. But, I had a- under-graduate student who was- they were the under-graduate project and he was assigned to me, and, he was measuring the intensities. I had developed a method of measuring intensities by- by, the people used to read them off a strip, but I discovered that the astronomers, there was an observatory in Cape Town, measured their stars' charge with a densitometer, which we didn't have in the Physics Department. So, I adapted a densitometer to make measurements, measurements of X-ray diffraction, that wasn't- it's hardly ever been done at the time. I know that Bragg himself at the Cavendish was making ways of densitometers.This worked very well, in fact, it was so- I got such accurate intensities, collected on the Weissenberg camera that you could see the hydrogen atoms. So, the- so, this all impressed James, and James thought I should go to Cambridge.
Kenneth Holmes was born in London in 1934 and attended schools in Chiswick. He obtained his BA at St Johns College, Cambridge. He obtained his PhD at Birkbeck College, London working on the structure of tobacco mosaic virus with Rosalind Franklin and Aaron Klug. After a post-doc at Childrens' Hospital, Boston, where he started to work on muscle structure, he joined to the newly opened Laboratory of Molecular Biology in Cambridge where he stayed for six years. He worked with Aaron Klug on virus structure and with Hugh Huxley on muscle. He then moved to Heidelberg to open the Department of Biophysics at the Max Planck Institute for Medical Research where he remained as director until his retirement. During this time he completed the structure of tobacco mosaic virus and solved the structures of a number of protein molecules including the structure of the muscle protein actin and the actin filament. Recently he has worked on the molecular mechanism of muscle contraction. He also initiated the use of synchrotron radiation as a source for X-ray diffraction and founded the EMBL outstation at DESY Hamburg. He was elected to the Royal Society in 1981 and is a member of a number of scientific academies.
John Finch is a retired member of staff of the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK. He began research as a PhD student of Rosalind Franklin's at Birkbeck College, London in 1955 studying the structure of small viruses by x-ray diffraction. He came to Cambridge as part of Aaron Klug's team in 1962 and has continued with the structural study of viruses and other nucleoproteins such as chromatin, using both x-rays and electron microscopy.