Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America, Chemistry Department, Rice University, Houston, Texas, United States of America.|Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America, Chemistry Department, Rice University, Houston, Texas, United States of America.|Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America.|vant Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.|Center for Theoretical Biological Physics, Rice University, Houston, Texas, United States of America, Chemistry Department, Rice University, Houston, Texas, United States of America.