Proteins and How to Make Them

The road to discovery is often winding, filled with obstacles and distractions, and littered with side-streets that lead to dead ends. Unmasking the true nature of proteins – complex molecules that are key to the microscopic processes underpinning all life – has been no different.

Kurt Wüthrich received the 2002 Nobel Prizes in Chemistry “for his development of nuclear magnetic resonance spectroscopy for determining the three-dimensional structure of biological macromolecules in solution”. This important contribution to allow the analysis and understanding of proteins in detail took Wüthrich 19 years, from his first use of nuclear magnetic resonance (NMR) to presenting the first NMR structure of a protein in 1984.

In his Agora Talk on Wednesday 29 June titled ‘Protein Large-Amplitude Dynamics by NMR Spectroscopy in Solution’, Wüthrich gave some insight into how this seminal contribution to science occurred. After a postdoctoral stint at the University of California, Berkeley, where he first used NMR spectroscopy to study the hydration of metal complexes, he moved to Bell Telephone Laboratories in New Jersey. “The first thing I did at Bell Labs was get blood of my own and study my haemoglobin,” recalled Wüthrich. “It made my career, essentially.”

Further study of haemoglobin, myoglobin and cytochrome cover the next two years gained him the attention of leading figures such as Max Perutz (1962 Nobel Prize for Chemistry), and most importantly confirmed to Wüthrich that NMR was a promising tool to obtain protein structures. “But I didn’t guess it would take 15 years,” he quipped.

Returning to his native Switzerland in 1969 to join ETH Zürich, Wüthrich toiled for seven years on the problem until a new crop of talent joined his group in 1976. The team developed new algorithms for the structural interpretation of NMR data and identified the nuclear Overhauser effect, soon leading to the first 2D NMR spectrum of a protein. It would take seven more years before they managed to structurally determine a globular protein for the first time.

Through his trials and tribulations in this work – and continuing ground-breaking NMR spectroscopy studies attempting to understand the mechanisms of signal transmission by G protein-coupled receptors – Wüthrich has learned a simple but invaluable lesson that all scientists should heed: “If you have fun in what you’re doing, you will almost automatically work hard and that leads to success,” he said. “When you have fun and your experiment fails, the time is not lost.”

Nature’s Protein Factory

Where Wüthrich studied the structure and dynamics of proteins, Venki Ramakrishnan (2009 Nobel Prize in Chemistry) was more interested in how they were made in nature’s protein factory: the ribosome.

But, as for Wüthrich, the path to discovery was long and winding. When he started out in the 1970s after his PhD, Ramakrishnan had no background in biology, he was a physicist.  “I had no idea what a ribosome even was,” he recalled in his Agora Talk ‘The Quest for the Structure of the Ribosome: Nature’s Ancient Protein Factory’ on Monday 27 June.

It was a feature in Scientific American that inspired him to explore biology as an alternative career choice. Immediately, he dove into the discipline with determination, uprooting his (very understanding) family multiple times, first to the University of California, San Diego, for graduate studies where he took undergraduate biology courses and lab rotations, then Yale University where he learned about neutron scattering techniques, and later taking various research and technical positions across the US.

By the late 1980s, his interest in the ribosome was at a fever pitch, but for others in biology it was regarded as a dead end. “The pioneers of the field like Francis Crick and Sydney Brenner (1962 and 2002 Nobel Prize in Physiology or Medicine, respectively) basically said, ‘We know that you have mRNA, you have a triplet code, you have tRNAs, and you have these ribosomes that put together amino acids – and so, intellectually, the problem is solved’,” he recounted. “The field sort of died out because to go from there to a really mechanistic understanding of how the ribosome works was an incredibly difficult problem.”

A sabbatical refining his knowledge of crystallography at the MRC Laboratory of Molecular Biology in Cambridge, UK, proved to be pivotal in proving the naysayers wrong. Ramakrishnan now thought that he had a unique way to attack the problem. “I felt that I had a completely different idea for how to phase the ribosome, although it turned out three of the four groups that did it actually used exactly the same idea.”

Two of these, led by Ada Yonath and Thomas Steitz (fellow 2009 Nobel Prize in Chemistry recipients), had already made significant progress in illuminating the structure of ribosomes, and were both determined to be the first to image them in high-resolution. “In cases like this, once someone has seen the ribosome, you don’t get kudos for being the second person to see it,” added Ramakrishnan. “Science is a mixture of competition and collaboration, and you can’t ignore the competitive side of it. And… competition in the ribosome case actually did help.”

Perhaps fittingly, the race to the ribosome ended in a draw. In August and September 2000, all three research groups published crystal structures with resolutions that allowed interpretation of the atomic locations, making it possible to map ribosome functionality at the most basic level.

Reflecting on his career, Ramakrishnan emphasised that it’s important not to get stuck in a scientific rut, as there’s always an escape route to something better: “If I did anything right, it was probably to keep giving myself second chances, to sort of stay in the game.”