Cation‐π (Na+‐Trp) interactions in the crystal structure of tetragonal lysozyme

Experimental evidence of a cation‐π interaction between a sodium cation (Na+) and the indole ring of residue Trpl23 in a structure (2. 0 Å) of hen egg‐white lysozyme is presented. The geometry of the metal ion‐π interaction observed in the protein structure (distance between the aromatic plane and the cation ∼4 Å) is consistent with geometries observed among small molecules crystal structures and quantum chemistry ab initio calculations. The present crystal structure of lysozyme provides unique structural information about the geometry of binding of cations to π systems in proteins. It shows that the metal ion‐π interaction within proteins is not significantly different from similar bindings found in small molecules and that it can be modeled by theoretical methods.

[1]  V S Lamzin,et al.  wARP: improvement and extension of crystallographic phases by weighted averaging of multiple-refined dummy atomic models. , 1997, Acta crystallographica. Section D, Biological crystallography.

[2]  R M Esnouf,et al.  An extensively modified version of MolScript that includes greatly enhanced coloring capabilities. , 1997, Journal of molecular graphics & modelling.

[3]  D Eisenberg,et al.  Where metal ions bind in proteins. , 1990, Proceedings of the National Academy of Sciences of the United States of America.

[4]  D A Dougherty,et al.  Acetylcholine binding by a synthetic receptor: implications for biological recognition , 1990, Science.

[5]  Sandro Mecozzi,et al.  Cation−π Interactions in Simple Aromatics: Electrostatics Provide a Predictive Tool , 1996 .

[6]  M. Vaney,et al.  High-resolution structure (1.33 A) of a HEW lysozyme tetragonal crystal grown in the APCF apparatus. Data and structural comparison with a crystal grown under microgravity from SpaceHab-01 mission. , 1996, Acta crystallographica. Section D, Biological crystallography.

[7]  D. A. Dougherty,et al.  Cation-π Interactions in Chemistry and Biology: A New View of Benzene, Phe, Tyr, and Trp , 1996, Science.

[8]  Jeffrey H. Williams,et al.  The molecular electric quadrupole moment and solid-state architecture , 1993 .

[9]  M Nayal,et al.  Valence screening of water in protein crystals reveals potential Na+ binding sites. , 1996, Journal of molecular biology.

[10]  D A Dougherty,et al.  Cation-pi interactions in aromatics of biological and medicinal interest: electrostatic potential surfaces as a useful qualitative guide. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[11]  J. Gershoni,et al.  Nuclear magnetic resonance (NMR) analysis of ligand receptor interactions: the cholinergic system--a model. , 1996, Critical reviews in biochemistry and molecular biology.

[12]  D. A. Dougherty,et al.  The Cationminus signpi Interaction. , 1997, Chemical reviews.

[13]  P. Howell,et al.  Structures of partridge egg‐white lysozyme with and without tri‐N‐acetylchitotriose inhibitor at 1.9 Å resolution , 1995, Protein science : a publication of the Protein Society.