SOLID-STATE NMR DETERMINATION OF INTRAMOLECULAR AND INTERMOLECULAR P-31-C-13 DISTANCES FOR SHIKIMATE 3-PHOSPHATE AND [1-C-13]GLYPHOSATE BOUND TO ENOLPYRUVYLSHIKIMATE-3-PHOSPHATE SYNTHASE

Rotational-echo, double-resonance (REDOR) P-31 NMR was used to obtain internuclear distances for shikimate 3-phosphate (S3P) and N-(phosphonomethyl)-[1-C-13]glycine (glyphosate) bound to 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase, a 46-kDa enzyme essential for the synthesis of aromatic amino acids in plants and microorganisms. An intermolecular P-31-C-13 distance of 7.2 angstrom was measured between the phosphate of S3P and the labeled carbon of glyphosate. This means that S3P and glyphosate are in proximity in the binding site of the enzyme. An intramolecular P-31-C-13 distance of 5.6 angstrom was measured between the phosphonate P-31 and the labeled carbon of glyphosate. This distance can be achieved only if glyphosate is completely extended when bound to EPSP synthase.