Dipartimento di Scienze Biochimiche
Università di Roma “La Sapienza” Piazzale A. Moro, 5
“Il Pescatore” is a small restaurant in Rome where I had dinner with Gregorio Weber in the mid sixties. He had visited Rome to discuss with Eraldo Antonini and Jeffreys Wyman the early stages of his ideas concerning multiple equilibria; at the end of the day, I brought him out for a “Rome-by-night” and dinner. During that pleasant interesting and relaxed evening, I felt how nice it would have been to work for a while with Gregorio. At the time I was already committed for a post-doc in Manfred Eigen’s Max Planck Institute in Goettingen; but a few years later (1968-69), I was able to organize (thanks to EMBO support) a 6 months visit to Urbana. At the time I was working in Rome on the reversible thermal unfolding of Aplysia myoglobin (a protein purified and characterized by Eraldo approximately 15 years before), which was endowed with the property of quick and reversible heat denaturation; part of this work, which was published only years later, involved the characterization of the apo-protein which is intrinsically more stable than the globin from horse or sperm whale.
A peculiarity of Aplysia myoglobin compared to the mammalian counterparts is that the two Trp are very distant in amino acid sequence. In sperm whale Mb the two Trp are both in the A-helix; on the other hand, in Aplysia one Trp is at the same topological position A12, but the other is in the H-helix, near the C-terminal; nevertheless the latter is topologically in the same corner of the globin, near the A-H helix contact, the area which was later shown to be part of the initial folding nucleus.
I was interested in studying the dynamic properties of the globin from Aplysia compared to sperm whale, and visited Gregorio’s Lab to carry out this small project given his worldwide reputation in protein fluorescence spectroscopy. My trip to Urbana involved landing in Chicago; however, I was not aware how to get to the final destination. When I asked information on flights to Urbana, a kind lady replied: “I am sorry but there are no flights to Urbana; you have to go by bus”. I was rather astonished since I knew that most places in the States are connected by air, but was unaware of the size of the town; thus I jumped on a bus, which took me down there in about ten hours. Only after arrival I realized that there were plenty of flights from Chicago to Champaign, and that Urbana-Champaign was effectively the same town, just divided by a road. When I told Gregorio, he laughed in his remarkable friendly style, which was so special.
My work in Urbana was very pleasant and literally full-time. I was working with Sonia Anderson who took her PhD with Gregorio himself, and afterwords spent one year of post-doc in Rome, working with Eraldo. Sonia was a wonderful person, a very nice lady and an excellent scientist; working with her was a pleasure and a very effective way of learning everything about fluorescence spectroscopy, as well as collecting lots of data. In a very short time I was updated with the subtelties, from basic theories to the most sophisticated instruments. She was a very good teacher and friend, fully devoted to science (as far as I could tell); quickly I discovered that life in Urbana was … quiet. I recall that period with a sense of nostalgia and feel that those months were the nearest I ever experienced to life in a Monastery: ora et labora.
We did all the necessary experiments on Aplysia apo-myoglobin and found something quite unexpected, which intrigued Gregorio. We were measuring relaxation times, and observed that there was a component of the intrinsic emission which had a rotational relaxation time of approximately 9 nanosec, i.e. much faster than the tumbling time of the whole protein (~ 23 nanosec). Obviously this was interpreted in terms of enhanced mobility of a sub-domain of the protein, which we attributed to the Trp located in the H helix that, under the condition of the experiment, was supposedly more frail than the A-helix. Some of these measurements made use of the phase modulation instrument built by Weber and Spencer to measure decay times, a splendid prototype of the highest quality, full of the latest technologies and gadgets, which I was very trilled about.
One day Gregorio proposed that we try some laser photolysis experiment on CO myoglobin, using a very powerful instrument with a pulse of ~20 nanosec (if I remember correctly). In the course of the experiments we found something curious and unexpected, which I was unable to rationalize. It emerged that the apparent quantum yield calculated from the fraction of CO photodissociated was dependent of the wavelength of the photolyzing pulse. This was quite irrational since we knew (from a famous 1947 paper by Bücher and Negelein) that the quantum yield for CO photodissociation in myoglobin is wavelength independent from UV to the red. During discussions, Gregorio came up with a complex interpretation which I did not understand at the time and have completely forgotten; data faded away in my note book. A posteriori, I regretted that the experiment was not attempted with hemoglobin because we may have stumbled on discovering geminate recombination earlier than others.
Over and above the science and all the wonderful people I met in Urbana, I had an enjoyable and relaxed time. Gregorio’s company and conversation was very pleasant; his humour and humanity, so typical of an Argentinian Jew, was very captivating. His attitude was condensed in a “lesson” addressed to a PhD student: “you are here to learn and understand, and not to work”. I know that people that came across Gregorio where all conquered by his natural charm, kindness and intelligence; I personally enjoyed very much listening at his own story, when as a medical student in Buenos Aires was encouraged by the famous physiologist B. Houssay to emigrate. It was the beginning of his wandering around, first to UK at Cambridge; thereafter to Sheffield (where he met and sympathize with Eraldo) and finally to Urbana. I had a unforgettable period with him, and every time I met him after my visit, I always enjoyed Gregorio’s his way of approaching life. In addition, at the end of the visit to Urbana, I met with my wife Federica in Boston and we had a wonderful trip in New England and Canada, an added value to a memorable period of my life.
| Gregorio Weber in Cambridge | The First Floor | Memories | Reminiscences | Gregorio Weber at Cambridge | Friendship Renewed in Sheffield | Gregorio Weber, friend and mentor |Gregorio Weber: Some recollections | Appreciation | Recollections of Gregorio | Gregorio | "Stay in Sheffield": Gregorio's Sage Advice | Gregorio as Teacher | Golden Age | Memories of the Biochemistry Department Sheffield, 1961 | My Best of Times: With Gregorio in Sheffield and Urbana 1954-1964 | Weber Memoir | A Roman Connection | My Mentor at Urbana, Rome, Corvallis| Gregorio Weber, A Great Gentleman of Science | Fond Memories | Two Memories in Parallel | A Superb Interaction | An Appreciation | Short snippets |