Aaron Klug
Aaron Klug was the scientist who finished [[rosalind-franklin|Rosalind Franklin]]'s groundbreaking work on [[tobacco-mosaic-virus|tobacco mosaic virus]] and — through a combination of mathematical insight and experimental discipline — then revolutionized biological microscopy. Born in 1926 in [[lithuania|Lithuania]] and raised in [[south-africa|South Africa]], he spent most of his remarkably productive career at the [[mrc-laboratory-of-molecular-biology|Medical Research Council Laboratory of Molecular Biology]] in [[cambridge|Cambridge]], one of the most concentrated collections of scientific talent in history. His development of crystallographic [[electron-microscopy|electron microscopy]], which earned him the 1982 [[nobel-prize-in-chemistry|Nobel Prize in Chemistry]], allowed researchers to build detailed three-dimensional models of biological complexes like [[chromatin|chromatin]] and [[transfer-rna|transfer RNA]] from flat images — a technique analogous to [[computed-tomography|computed tomography]] but applied at the molecular level. He died at the age of ninety-two on November 20, 2018, having shaped structural biology more profoundly than almost anyone outside the original [[dna|DNA]] circle.
The Franklin Connection
Klug joined [[rosalind-franklin|Rosalind Franklin]]'s small but focused research group at [[birkbeck-college|Birkbeck College]] in [[london|London]] in 1954, after the [[dna|DNA]] structure had already been solved and Franklin had turned her attention to viruses. They worked closely together on the deceptively complex structure of [[tobacco-mosaic-virus|tobacco mosaic virus]] — a rod-shaped plant virus that had become a key model system for understanding how [[protein|proteins]] and [[nucleic-acid|nucleic acids]] assemble — until Franklin died of [[ovarian-cancer|ovarian cancer]] in 1958 at just thirty-seven. Klug, who felt a deep obligation to his mentor, completed the structural work, ultimately publishing the definitive structure: a hollow rod of 2,130 identical protein subunits arranged in a helix around a single strand of [[rna|RNA]], and became an important advocate for Franklin's scientific legacy. He wrote a detailed biographical memoir — one that provided the most thorough and sympathetic account of her real contribution to [[dna|DNA]] research, directly counterbalancing [[james-watson|James Watson]]'s dismissive portrayal in [[the-double-helix|The Double Helix]] — for the [[royal-society|Royal Society]] that helped preserve her place in the history of science.
Crystallographic Electron Microscopy
His Nobel-winning contribution was the development of crystallographic [[electron-microscopy|electron microscopy]] — a way to determine three-dimensional structures from two-dimensional images. The deceptively simple key was combining images taken at many different angles with [[fourier-analysis|Fourier analysis]], a form of mathematical reconstruction — a technique long used in [[x-ray-crystallography|X-ray crystallography]] that Klug was the first to systematically apply to the electron microscope. Using this painstakingly refined method, he and his collaborators determined the three-dimensional structures of several fundamental biological complexes — most importantly the [[nucleosome|nucleosome]], the basic unit of [[chromatin|chromatin]], in which [[dna|DNA]] wraps around a core of eight [[histone|histone]] proteins like thread around a spool. The nucleosome structure, which Klug's group solved through years of patient work, explained how cells — all of which carry identical DNA — regulate [[gene-expression|gene expression]]: how one genome can produce hundreds of different cell types, because the same genes can be active or silent depending on how tightly the [[dna|DNA]] is [[epigenetics|epigenetically]] packaged.
Legacy
Klug served as director of the legendary [[mrc-laboratory-of-molecular-biology|LMB]] from 1986 to 1996, overseeing a laboratory where [[francis-crick|Crick]], [[max-perutz|Perutz]], [[frederick-sanger|Sanger]], [[sydney-brenner|Brenner]], and a dozen other [[nobel-prize|Nobel]] laureates had worked. He was knighted and elected president of the [[royal-society|Royal Society]], receiving virtually every major honor available to a British scientist. Yet he remains far less famous than many of the researchers whose own discoveries his techniques made possible — a pattern common in science, where the builders of instruments are remembered less vividly than those who use them to make headline discoveries. The [[cryo-electron-microscopy|cryo-electron microscopy]] revolution of the 2010s — which earned [[jacques-dubochet|Dubochet]], [[joachim-frank|Frank]], and [[richard-henderson|Henderson]] the 2017 [[nobel-prize|Nobel]] — was built directly on the mathematical framework Klug quietly established half a century earlier.