Solid-state NMR determination of intra- and intermolecular 31P-13C distances for shikimate 3-phosphate and [1-13C]glyphosate bound to enolpyruvylshikimate-3-phosphate synthase.

Rotational-echo, double-resonance (REDOR) 31P NMR was used to obtain internuclear distances for shikimate 3-phosphate (S3P) and N-(phosphonomethyl)-[1-13C]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 31P-13C distance of 7.2 A 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 31P-13C distance of 5.6 A was measured between the phosphonate 31P and the labeled carbon of glyphosate. This distance can be achieved only if glyphosate is completely extended when bound to EPSP synthase.