Guillermo Montoya was born in Madrid in 1967. He graduated in Biochemistry from the University of the Basque Country in 1990, and gained his doctorate in Chemistry from the University of Zaragoza in 1993. He was awarded grants by the European Molecular Biology Organisation (EMBO) and the Federation of European Biochemical Societies (FEBS) to undertake a postdoctoral stay, and he went to the Max Planck Biophysics Institute in Frankfurt am Main (Germany), where he worked on the crystallisation of membrane proteins in the group of H. Michel. Subsequently and thanks to an EMBO long-term grant and another Marie Curie grant (EU), he travelled to the European Molecular Biology Laboratory (EMBL) in Heidelberg (Germany), where he remained for 9 years performing pioneering studies of the structure of the signal recognition particle (SRP), a complex ribonucleoprotein essential in the biogenesis of membrane proteins.

In 1998 he was named Researcher of the Superior Science Research Council (CSIC) and he was awarded a grant from the Peter und Traudl Engelhorn Foundation. From 2003 to 2008, he was Honorary Professor of Biochemistry in the Autonomous University, Madrid, and member of the working group assigned to the design of the light crystallography in the Spanish synchrotron (ALBA).

By using protein engineering, the group of Dr. Montoya has redesigned the specificity of proteins recognising DNA. These redesigned enzymes may be used to stimulate homologous recombination by double chain breakage, inducing the repair of defective genes at very low levels of toxicity. The use of these redesigned proteins opens up new possibilities for gene therapy in patients with single gene diseases. In 2009 he was awarded the National Prizes of the Mutua Madrileña Foundation and the Caja Rural de Granada Foundation, Ministry of Health.