Small molecules containing hetero-bicyclic ring systems compete with UDP-Glc for binding to WaaG glycosyltransferase Jens Landström,a Karina Persson,b Christoph Rademacher,c Magnus Lundborg,a Warren Wakarchuk,d Thomas Peters,c and Göran Widmalm*,a a Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden b c Department of Chemistry, Umeå University, S-901 87 Umeå, Sweden University of Luebeck, Institute of Chemistry, Ratzeburger Allee 160, 23538 Luebeck, Germany d National Research Council of Canada, Institute for Biological Sciences, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada Supporting information Table S1. 1H NMR chemical shift assignments (ppm) and proton-proton coupling constants (Hz) in parenthesis for uridine, UMP, UDP, UDP-Glc and UDP-Gal at pH 8.2 and 298 K. Chemical shifts and coupling constants were refined using the PERCH NMR software. Uridine UMP UDP UDP-Glc UDP-Gal H5 5.91 (8.1) 5.99 (8.1) 5.97 (8.1) H5 5.98 (8.1) H1'' 5.61 (3.5, 7.2) H5 5.98 (8.1) H1'' 5.65 (3.7, 7.2) H6 7.89 8.12 8.01 H6 7.95 H2'' 3.55 (9.9, 2.8) H6 7.95 H2'' 3.82 (10.3, 2.8) H1' 5.94 (4.5) 6.01 (5.3) 5.97 (4.6) H2' 4.37 (5.4) 4.43 (5.2) 4.45 (5.3) H3' 4.25 (5.5) 4.36 (4.1) 4.40 (4.6) H4' 4.15 (3.0, 4.5) 4.26 (2.7, 3.0, 1.7) 4.27 (2.7, 2.9, 2.1) H51' 3.82 (-12.8) 4.02 (-11.8, 3.7) 4.22 (-11.9, 4.3) H52' H1' 6.00 (4.7) H3'' 3.78 (9.2) H2' 4.38 (5.7) H4'' 3.48 (10.2) H3' 4.38 (5.3) H5'' 3.90 (4.5, 2.3) H4' 4.30 (2.5, 3.0, 1.4) H6R' 3.79 (-12.4) H51' 4.21 (-11.8, 5.6) H6S' H52' 4.21 (4.4) H1' 6.00 (4.9) H3'' 3.92 (3.3) H2' 4.38 (5.3) H4'' 4.03 (1.2) H3' 4.38 (4.2) H5'' 4.17 (7.6, 4.8) H4' 4.30 (2.6, 3.0, 2.1) H6R' 3.76 (-11.8) H51' 4.21 (-11.8, 5.6) H6S' S1 3.92 3.97 (5.1) 4.25 (6.3) 3.86 3.74 H52' 4.21 (4.5) Figure S1. Transverse relaxation rate for uridine as a function of concentration. R2 from protons H6, H5 and H1' are denoted by filled circles, triangles and open circles, respectively. The obtained KD values for uridine were 0.4 ± 0.1 mM, 0.7 ± 0.2 mM and 0.7 ± 0.1 mM, respectively, with R > 0.99 in all cases. Figure S2. STD signal intensity ratio for uridine (averaged for H6, H5 and H1') as a function of UDP concentration, where STD0 is the signal intensity in the absence of UDP. The obtained KD value for UDP was 9 ± 0.04 M with R > 0.999. S2