biostudies-literaturePrasad SNHLBI NIH HHS13785-90https://www.ebi.ac.uk/biostudies/studies/S-EPMC283499biostudies-literatureUnknown100(24)Monovalent-cation-activated enzymes are abundantly represented in plants and in the animal world. Most of these enzymes are specifically activated by K+, whereas a few of them show preferential activation by Na+. The monovalent cation specificity of these enzymes remains elusive in molecular terms and has not been reengineered by site-directed mutagenesis. Here we demonstrate that thrombin, a Na+-activated allosteric enzyme involved in vertebrate blood clotting, can be converted into a K+-specific enzyme by redesigning a loop that shapes the entrance to the cation-binding site. The conversion, however, does not result into a K+-activated enzyme.Proceedings of the National Academy of Sciences of the United States of AmericaRedesigning the monovalent cation specificity of an enzyme.PMC283499R01 HL049413HL58141R29 HL049413R01 HL073813HL49413HL73813R01 HL058141Banerjee Roy DPrasad SDi Cera EBush LACantwell AMWright KJfalseRedesigning the monovalent cation specificity of an enzyme.Monovalent-cation-activated enzymes are abundantly represented in plants and in the animal world. Most of these enzymes are specifically activated by K+, whereas a few of them show preferential activation by Na+. The monovalent cation specificity of these enzymes remains elusive in molecular terms and has not been reengineered by site-directed mutagenesis. Here we demonstrate that thrombin, a Na+-activated allosteric enzyme involved in vertebrate blood clotting, can be converted into a K+-specific enzyme by redesigning a loop that shapes the entrance to the cation-binding site. The conversion, however, does not result into a K+-activated enzyme.2003-01-01T00:00:00Z2003 Nov2025-04-26T04:21:10.777Z2019-03-26T23:52:09ZS-EPMC2834991461256510.1073/pnas.2333109100