Professor Mario Mammi died on December 20, 2006 in Padova, Italy. He was born in Reggio Emilia in 1932. He began to study Chemistry at the University of Modena, and he graduated with honors from the University of Padova. Here, he started his career as a research assistant of Silvio Bezzi, a professor of organic chemistry and founder of the Institute of the Organic Chemistry at the beginning of the 1950’s. Prof. Bezzi strongly believed in the potential of x-ray diffraction for solving problems in organic chemistry and he decided to establish a crystallography group in the Institute, under the supervision of Mario Mammi. Initially, the research interest of the group was mainly devoted to the structure determination of organic compounds, to understand their reactivity in general and in polymerization reactions. The most important breakthrough was the determination of the structure of thio-thiophten, which allowed the definition of a new kind of aromatic system. The structure, determined from projections without the use of computers (in those times, most of the calculations were performed manually, by using ingenious devices to speed up calculations), was published in Nature in 1958.
At the beginning of the 1960’s, Mario Mammi’s scientific interest shifted towards protein crystallography. He spent some time at the Laboratory of Molecular Biology in Cambridge in 1962 and 1964, but his second stage was interrupted by the sudden death of Prof. Silvio Bezzi, which forced him to return to Padova to manage the research group. Major scientific contributions of this period were on the diffraction of biological fibers, in particular elastin, a protein that obviously could not be crystallized and for which even a fiber diffraction spectrum was hard to obtain. Work on globular proteins in Padova started with Ribonuclease. This is a bovine enzyme that catalyzes the hydrolysis of the phosphodiester bond of RNA; its three-dimensional structure had been determined independently by two groups (a first low resolution model appeared in 1967 by Wyckoff and by Kartha and Harker). In Ribonuclease, the bond between residues 20 and 21 can be specifically hydrolyzed, and the two resulting portions mixed together can recombine, giving an active enzyme, despite the lack of a covalent bond. This feature was used in Padova to produce an artificial enzyme putting together the bigger fragment with a synthetic 1-20 peptide in which one or more amino acids had been modified with respect to the wild-type protein. This allowed the production of a sort of point-mutants ante litteram, well before molecular biology was established, and to study the relevance of single amino acids on overall protein conformation. The first (and only) structure of one of these artificial “mutants”, Orn-10-RNAase S’, appeared only some years later.
In 1971, Mario Mammi was appointed Full Professor and in 1975, he became the Director of the Biopolymer Research Center of the Italian National Research Council (CNR). The Center was hosted in the Institute of Organic Chemistry of the University and included not only the protein crystallography group, but also peptide and protein chemistry and, later, NMR. With time, Mario Mammi became more and more involved not only in the administration of the Center, but also in other managerial responsibilities, either in Rome with CNR or in Padova, and he applied himself to these commitments with great dedication. Among many other things, he was head of the Department of Organic Chemistry (Nov. 1972 – Nov. 1975) and vice-Rector of the University (1993-1996). From 2005, he was in charge of the University budget. He was among the founders of the Italian Association of Crystallography, and served as its President from 1985 to 1987. He was several times the editor of the Italian section of the World Directory of Crystallographers. Mario Mammi was diagnosed with lung cancer in February last year, but he continued to work and tend to University business till summer, when his health prevented him from leaving home. His great wisdom, his proverbial fairness, his unusual sense of the institutions, and his unforgettable smile will be sorely missed.
S. Mammi, P. Spadon, G. Zanotti