In memory of Prof. Luis Moroder

I was deeply shocked to hear the sad news about Prof. Luis Moroder. It made me realize once again how significant his presence was to us. Given my long-standing friendship, I received a request from an editor to contribute a memorial tribute. In response, I would like to share some of my cherished memories. In the 1970s, peptide chemistry flourished focusing on organic chemical synthesis methods. The Akabori Conference, named after Dr. Shiro Akabori, has been biennially held as a venue for exchanges between German peptide scientists, initially led by Prof. Wunsch and later by Prof. Moroder, and Japanese scientists, including Sakakibara and Shiba. Over time, the interests of peptide researchers expanded to the structure–activity relationships of bioactive peptides, extending into the fields of physical chemistry and molecular physiology. For example, Moroder's achievements are said to include over 500 published papers. While Huber will summarize these achievements in a memorial article in this special issue, I will limit myself to sharing one episode of my interaction with him. At the Institute for Protein Research of Osaka University, we were exploring methods for analyzing the solution structure of peptides. We found that endothelin, a peptide with a strong vasoconstrictive activity derived from vascular endothelial cells, and a series of neurotoxic peptides, commonly contain two peptide fragments with the amino acid sequences -Cys-X-X-X-Cys- and -Cys-X-Cys-. When these fragments are linked by disulfide bonds, the -Cys-X-X-X-Cys- part forms an α-helix structure, and the -Cys-X-Cys- part forms an extended structure such as a β-strand. We called this sequence the CSH motif, considering it a motif for α-helix formation. Furthermore, we substituted various amino acid residues for X and analyzed the changes in its structure and activity using superconducting nuclear magnetic resonance (NMR) and distance geometry methods (DG) which were under development at that time. Prof. Moroder showed great interest in this research. Utilizing grants from the Japan Society for the Promotion of Science, I invited researchers to my lab for 3 months each, including Moroder as a special professor of Osaka University. I was not good at organizing, and my lab desk was cluttered with numerous data and literature related to the CSH motif. Even before coming to Osaka, Prof. Moroder suggested that he would help organize the desk so that I could complete the paper. Actually, his help and the cooperation of postdocs and young researchers in my lab made it possible to complete the paper, which is titled “Folding motifs induced and stabilized by distinct cystine frameworks,” published in Protein Engineering, vol. 11, no. 8, pp. 649–659, 1998. I appreciated his methodical and precise work. Since then, Moroder has become our good adviser and mentor. Prof. Luis Moroder was from the mountainous region of South Tyrol, and one of Luis' brothers, Enrico, is the famous wood sculptor. Luis was very proud of him. Furthermore, the world famous music producer, Giorgio Moroder, is Luis' cousin. Luis was also a renowned scientist, and he took pride in being world-famous alongside his family. He experienced different cultures with different histories, starting from a small town in the mountains to Italy, Germany, France, and the United States. He had a deep interest in Japanese culture and often asked for explanations. Through this process, he made many Japanese scientist friends. He believed that while Americans and Japanese love well-chilled beer and wine, Germans love the aroma of room-temperature drinks. Even when served cold beer at dinner, he would warm it by holding the bottle in his hand. He actively experienced various colorful Japanese foods, but for some reason, he could not get used to tofu. Prof. Moroder was often accompanied by his wife, Anne Marie, to various international conferences and other events. She is a very sociable person. I also remember that she frequently played the role of an excellent hostess with Luis. Both of them are wonderful people. I extend my heartfelt condolences to Luis Moroder and express my gratitude for our international friendship. Once again, I would like to extend my deepest sympathies.