Sir Aaron Klug was a Lithuanian-born British molecular biophysicist who made foundational contributions to structural biology. Born in Zelvas, Lithuania on August 11, 1926, he was brought to South Africa as a child and later moved to England for his education. He completed his PhD in solid-state physics at Trinity College Cambridge in 1953, where he developed a strong interest in the structure of matter and how it was organized. After working at Birkbeck College with Rosalind Franklin on virus structures, he joined the Medical Research Council Laboratory of Molecular Biology in Cambridge in 1962, marking the beginning of his most influential scientific period.
Klug's most significant contribution was the development of crystallographic electron microscopy, which ingeniously combined techniques from electron microscopy and X-ray diffraction to recover three-dimensional structural information from two-dimensional electron micrographs. This breakthrough enabled the structural elucidation of complex biological assemblies including viruses, transfer RNA, chromatin, and zinc finger proteins, revealing critical insights into their functional mechanisms. His work with DeRosier on the three-dimensional reconstruction technique created a revolution in structural molecular biology, allowing for hundreds of macromolecular structures to be determined and forming the basis for modern techniques like cryo-electron microscopy. For these pioneering developments, he was awarded the sole 1982 Nobel Prize in Chemistry, with the Nobel Committee specifically recognizing his 'development of crystallographic electron microscopy and his structural elucidation of biologically important nucleic acid-protein complexes'.
Beyond his technical innovations, Klug made several key biological discoveries including the crystal structure of yeast phenylalanine tRNA in 1974 and the identification of zinc finger proteins in 1985, which revealed a modular protein structure capable of binding specific DNA sequences with remarkable precision. His leadership extended beyond the laboratory as he served as Director of the MRC Laboratory of Molecular Biology from 1986 to 1996 and as President of the Royal Society from 1995 to 2000, where he championed scientific research and evidence-based policy. Klug's work on neurodegenerative diseases also contributed to our understanding of tau protein in Alzheimer's disease, demonstrating the breadth of his scientific impact. He passed away on November 20, 2018, leaving behind a legacy that continues to shape structural biology and our molecular understanding of life processes, with modern cryo-EM techniques directly evolving from his initial breakthroughs in image processing and three-dimensional reconstruction.
