Padrón work started at Cambridge´ MRC Laboratory of Molecular Biology. He founded I.V.I.C.´s Center of Structural Biology, where he was an International Research Scholar of Howard Hughes Medical Institute. His lab and collaborators found: (1) by cryo-EM that in thick filaments of tarantula muscle the two heads form the myosin interacting-heads motif (IHM), where both ATPases were inhibited explaining relaxation (Nature 436: 1195, 2005). (2) that IHM is conserved since before the origin of animals revealing IHM importance as a relaxation ATPase inhibition and ATP energy-saving mechanism. (3) that a cooperative phosphorylation activation mechanism explains potentiation and post-tetanic potentiation on tarantula contracting muscles. (4) that mutations of hypertrophic cardiomyopathy concentrate on human cardiac IHM intramolecular interactions accounting for altered contractility, reduced diastolic relaxation, and increased energy consumption. Honors: Polar Prize, CONICIT and FONACIT Biology Prizes and National Prize in Science and Technology of Venezuela. Elected member of Latin-American Academy of Sciences in 2002, elected member of The Worl Academy of Sciences (TWAS) in 2004 and elected foreign associate of U.S. National Academy of Sciences in 2018.