One site fits both: A model for the ternary complex of folate + NADPH in R67 dihydrofolate reductase, a D2 symmetric enzyme. - Elizabeth E. Howell; Ushma Shukla; Stephanie N. Hicks; R. Derike Smiley; Leslie A. Kuhn; Maria I. Zavodszky (J. Comput. Aided Mol. Des., 2001)