STEREOCHEMISTRY OF PHOSPHATE-LEWIS ACID INTERACTIONS - IMPLICATIONS FOR NUCLEIC-ACID STRUCTURE AND RECOGNITION

The geometry of phosphate-Lewis acid interactions has been examined by using the Cambridge Structural Database. Interactions involving metal ions display preferentially syn, unidentate, and out-of-plane coordination stereochemistry with regard to the phosphinyl (-PO2--) group. In contrast, hydrogen bond donors display a very slight preference for anti stereochemistry with the phosphinyl group, and these interactions do not tend toward in-plane interaction with the phosphinyl group. In general, preferential phosphate-Lewis acid geometry contrasts markedly with carboxylate-Lewis acid geometry, and our results are useful in the interpretation of nucleic acid structures and protein-nucleic acid interactions observed by macromolecular X-ray crystallography. Another application of our results concerns the use of phosphinyl derivatives as transition-state analogues; the electronic distribution of the phosphinyl moiety approximates that of the proteolytic transition state, but we present an upper limit to this approximation. © 1990, American Chemical Society. All rights reserved.