Gregorio Weber (4 July 1916 – 18 July 1997) was an Argentinian scientist who made significant contributions to the fields of fluorescence spectroscopy and protein chemistry. Weber was elected to the National Academy of Sciences in 1975.
Early life and education Gregorio Weber was born in Buenos Aires, Argentina in 1916. He attended the University of Buenos Aires where he received his Doctor of Medicine degree in 1942. He worked as a medical student from 1939 to 1943 in the Department of Physiology and Biochemistry as a teaching assistant for Bernardo Alberto Houssay. Houssay was renowned as a physiologist for his work on the endocrine system and in particular the pituitary gland, and shared the 1947 Nobel Prize for Physiology and Medicine. Weber continued his studies at the University of Cambridge under the guidance of Malcolm Dixon, well-known enzymologist, and, in 1947, earned a Ph.D. in biochemistry. His thesis, titled "Fluorescence of Riboflavin, Diaphorase and Related Substances", marked the beginning of the application of fluorescence spectroscopy to biomolecules. Weber’s thesis was devoted especially to measurements of the quenching of fluorescence of riboflavin, and on development of a general theory of quenching by complex formation. This led to his first publication, the first to demonstrate that fluorescence quenching can take place after formation of molecular complexes of finite duration rather than collisions. His second publication was the first demonstration of an internal complex in FAD. Years later he was to follow up this work with the first demonstration that NADH also formed an internal complex and with more complete characterizations of the excited state properties of FAD and NADH. From 1948 to 1952 Weber carried out independent investigations at the Sir William Dunn Institute of Biochemistry at Cambridge, supported by a British Beit Memorial Fellowship. He began to delve more deeply into the theory of fluorescence polarization and also began to develop methods which would allow study of proteins that did not contain an intrinsic fluorophore such as FAD or NADH. To this end, he invested considerable time and effort in synthesizing a fluorescent probe that could be covalently attached to proteins and which possessed absorption and emission characteristics appropriate for the instrumentation available in post-war England. The result of two years of effort was the still popular probe dimethylaminonaphthalene sulfonyl chloride or dansyl chloride. With this tool in hand and with new instrumentation he began to investigate several protein systems, publishing his theory and experimental results in two classic papers published in 1952, The theory paper extends Perrin’s theory of depolarization due to rotation of ellipsoidal molecules. Specifically, Weber showed that Perrin’s complex equations, which required a knowledge of the orientation of the fluorophore’s absorption and emission oscillators with respect to the axis of rotation of the ellipsoid, could be considerably simplified if the fluorophores carrying the oscillators were assumed to be randomly oriented on the macromolecule. This paper also contained a formulation of the law of additivity of polarizations. Weber stayed at Cambridge as an independent researcher until 1953 when Hans Krebs recruited him for the new Biochemistry Department at Sheffield University.
University of Illinois In the early 1960s, Irwin “Gunny” Gunsalus, then the head of the Biochemistry Division of the Department of Chemistry at the University of Illinois at Urbana-Champaign, recruited Weber. Gunsalus related the story that while he was convincing his colleagues that Gregorio Weber was an exceptional scientist, someone commented that Weber didn’t have as many publications as one might expect from a senior professor. Gunny explained that while this was true, Weber’s ratio of outstanding papers to total papers was unity and that this ratio — known thereafter as the Weber ratio — was certainly the more important consideration. Gregorio Weber joined the University of Illinois in 1962 and built a research program that continued actively until his death from leukaemia on July 17, 1997. During the early years in Urbana, he continued to develop novel fluorescence instrumentation and probes and extended his studies of protein systems.
Scientific contributions Gregorio Weber was responsible for many of the more important theoretical and experimental developments in modern fluorescence spectroscopy. In particular, he pioneered the application of fluorescence spectroscopy to the biological sciences. His list of achievements includes the following:
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