Biochemistry undergraduate Josie Pepper recently interviewed eminent scientist, and Brasenose tutor, Professor Elspeth Garman. Here's her write up of the interview.
X-ray crystallography is a scientific technique that screams success. Its application in the chemical and biological sciences has led to 28 Nobel Prizes, while the protein structures it elucidates underpin nearly all meaningful biochemical research today. Yet perhaps the true heroes are not the scientists parading their discoveries in the limelight, but those working behind the scenes, those pioneering the technology, machines, and methodology needed to maintain the pace of scientific progression we have become accustomed to.
Professor Elspeth Garman, a Senior Kurti Research Fellow in Molecular Biophysics at Brasenose College and in her fourth and last year as Tutor for Graduates, seems to be comfortable avoiding attention: “Prizes are very, very nice but I don’t need them. I don’t think I’ve ever been very ambitious. I’ve surpassed what I ever dreamed I would do.” What she has done, however, has shaped the face of modern science. This has been recognised with a number of awards, recently the 2015 Hamburg Mildred Dresselhaus Senior Award and Guest Professorship—“I’m going next week as the after-dinner speaker to address female physicists from all over Germany. It has also provided funds to take graduate students over there so I can do some experiments [with them], talk with people, and generally be an old woman chatting over coffee!”—and the 2016 Fankuchen Award from the American Crystallographic Association, awarded every three years “to recognise contributions to crystallographic research by one who is known to be an effective teacher of crystallography.”
The award that Professor Garman least expected, “the most extraordinary,” was her 2014 Women’s International Film and Television Showcase Humanitarian Award, after her BBC Radio 4 ‘Life Scientific’ interview with Jim Al-Khalili was put on the BBC World Service and National Public Radio in the USA. “I’ve never been on film or owned a TV in my life, and I deleted the first few emails, thinking they were spam. That was very unexpected.”
Elspeth works at the interface of all three core sciences, developing physical techniques to improve the study of the chemical properties of biological molecules. “The way I explain what I do to people I meet on buses is that I find the three-dimensional shape of big [by molecular standards], biologically important molecules. These are proteins, which are like strings of beads that wrap up like wet spaghetti.” Knowing the shape of these proteins can help biochemists to understand the mechanisms underlying their cellular function, allowing use of this knowledge for therapeutic benefit. “For example, from knowledge of the 3D shape of insulin it has been possible to make a synthetic insulin which is absorbed more slowly by diabetics, so they benefit by not having to inject themselves with it so often.”
However, finding the structure of these tiny, sub-microscopic proteins is very challenging. “The method we use sounds ridiculous: we grow crystals. These are the biological molecules lined up like soldiers, but three-dimensionally, so upwards as well. It’s not like a diamond crystal, which is hard & only has carbon in it, because we have gaps between our blobby molecules which have liquid in. It’s like these soldiers are in a swimming pool. If they are removed they tend to bend and not to stand to attention in same way; [to find their structure] we rely on the fact that all the soldiers are standing to attention in the same way to get our [X-ray] scattering. We hit them with ‘cannon balls’—X-rays—and get piles of cannon balls back, and from that we can deduce back the shape of the soldier—the biological molecule.”
Growing the crystal is by far the greatest challenge of the technique. Scientists can still not predict the conditions that will best allow it to grow and mostly rely on luck. “It’s trial & error. In a recent project we tackled, an enzyme from the tuberculosis bacterium, we set up seven thousand crystallisation conditions and we only ever grew one crystal. It was only 23 microns [one fiftieth of a millimetre] in size.”
Since obtaining these protein samples is so difficult, it is crucial to be able to get as much information out of each crystal as possible. This is where Elspeth comes in. “The things I’m known for are development of cryo-crystallographic techniques where we plunge-cool the protein crystals, having treated them so that they don’t get too damaged [by ice crystals that form with slow-cooling], into liquid nitrogen. Why do we do that? Because we get on average seventy times more data at cryo-temperatures than we get at room temperature, which means you can sometimes get an entire data set from one crystal, whereas at room temp you need tens of crystals because the radiation damage is so intense.”
This technique has been so successful that almost 90 percent of the X-ray structures of proteins in the Protein Data Bank, the primary reference database of protein structures, are found in this way. Yet most scientists that find and use these structures might be surprised to hear of the “gizmos” that Professor Garman came up with to use in the high-tech machinery. “We loop the crystal up in a fibre loop. We tried tooth floss and fishing wire, but the best was fibres from [Professor Dame] Louise Johnson’s mohair jumper. I also found that my baby’s hair was very fine and had low X-ray scattering from it, so we could make very nice loops from it. And it was much easier to tie under the microscope if I had the root! She used to cover her head with her hands when she saw me coming!”
The cryo-crytallography technique was Elspeth’s first major success, establishing her status in the crystallographic community and allowing her to teach at 75 summer schools worldwide over the past twenty years, “a fantastic ticket!” Next she turned her hand to improving the method further by minimising the damage done to the sample by the X-ray radiation with which it is bombarded. In the same way that human tissue is damaged when exposed to too much X-ray radiation, the delicate protein crystals can be degraded when subjected to the high intensity beam, producing misleading structural information even when held at 100K (-173°C). “This is what my group now look at, trying to quantitate it and correct the data to try to give people an idea of how many X-rays they can put on their biological sample before the information yielded is compromised.”
“It turns out that it doesn’t damage uniformly through the whole structure, but particular amino acids [the building-block subunits of proteins; the ‘beads’ on the necklace] are susceptible. So we have had to learn some radiation chemistry as well as some biology.” Professor Garman, a nuclear physicist by training, has adapted her skills as a physicist to be of use to biology, but—eager as ever to point out her own limitations—claims to understand very little of the information it yields. “My guts are a physicist’s. I can’t remember the biology; it doesn’t stay in my brain. I changed field in 1987 and my biochemistry is dreadful which is very embarrassing!”
The evidence would suggest that she does herself an injustice. In 2006 she and her student published a seminal paper giving the experimental X-ray dose limit, which is known as the Garman limit. And here, thankfully, Elspeth allows herself a little glory: “It is great to have something named after you. It was the best experiment I’ve ever thought of and I’m very proud of the way we did it.”
The techniques Professor Garman has, and is, developing and adapting are not only pushing biochemical research forward, but also highlighting errors in established science. Using microPIXE, a technique for characterising metal atoms (which can occur in some proteins known as metalloproteins) that “came from my nuclear physics roots”, Elspeth and her team have found that nine of the 29 metalloproteins they looked at had been logged in the Protein Data Bank with incorrect metals. “A third [of the metalloproteins we tested] had the wrong metal recorded, so possibly up to 30 percent [in the Data Bank] have the wrong metal.” This has significant implications for biochemistry, since metals found in proteins are usually implicated in the protein’s cellular and metabolic function. Identifying which proteins are incorrect is a long-term project for Elspeth and some of her students.
It is clear that curiosity, intrigue, and a steadfast will to constantly tweak, refine, and push the boundaries of what biochemistry can achieve are far greater driving forces for Elspeth than any wish for personal recognition or validation. And more than that, her main motivation lies with her graduate students. “The greatest fun I have is with my graduate students. Now I push publications to get our results out there & so my students have publications,” rather than to further her own career.
“Graduate students give you three years of their life to study something you’re interested in. It’s an amazing gift. I feel a responsibility to make sure they network, do something positive, enjoy what they’re doing, get publications, can get a good job afterwards, and learn respect for the human race. In my view I owe them. All my research has been made possible by graduate students.”
It’s easy to wonder how the study of science has changed since Elspeth’s own time as a graduate student, especially since she was the first female graduate student in Oxford in her field for fifteen years. Sexism in science clearly has left an impression. “You bore the flag for all womankind. If you did something stupid it was because women were stupid, not because Elspeth made a mistake. I found that difficult. Also when I was younger, collaborators and people who wanted to talk science with me got teased by the other men. I tended to just plough on.”
Yet she also highlights that attempts to narrow the gender gap can be just as humiliating as being trapped by it. “When, as post-doc, I went to my first international meeting in Berkley, San Francisco there were 992 men and eight women. The Equal Rights Amendment had just come in the States and the physics departments in the USA had been told they had to recruit a female nuclear physicist. In five days I was offered twelve jobs, only one of which was a genuine fit for my experience, research interest, and papers. It was the most demeaning, degrading experience; job offers just because I was female. Unfortunately in the States a few women were taken on in nuclear physics who shouldn’t have been, filling quotas rather than selecting the best candidate. Subsequently more women weren’t welcomed as the earlier one had been no good. This back lash was quite serious & makes me very hesitant about positive discrimination. All my life I’ve been asked to give talks about being a female scientist. My answer is I am a scientist who happens to be female, I am not a female scientist.”
It seems that a quiet but steely determination has helped her climb to where she is now. Early in her career, wanting to work part-time, she proffered “The best line of my life” to the professor who was reluctant to allow this, “‘You’ll have part of my time, but all of my brain.’” Thoughtful, measured responses to all challenges, be they scientific, personal, or career-related, are clearly Elspeth’s speciality.
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