Exploring the influence of the protein environment on metal-binding pharmacophores.Martin, D.P., Blachly, P.G., McCammon, J.A., Cohen, S.M.
(2014) J Med Chem 57: 7126-7135
- PubMed: 25116076
- DOI: https://doi.org/10.1021/jm500984b
- Primary Citation of Related Structures:
4Q7P, 4Q7S, 4Q7V, 4Q7W, 4Q81, 4Q83, 4Q87, 4Q8X, 4Q8Y, 4Q8Z, 4Q90, 4Q99, 4Q9Y
- PubMed Abstract:
The binding of a series of metal-binding pharmacophores (MBPs) related to the ligand 1-hydroxypyridine-2-(1H)-thione (1,2-HOPTO) in the active site of human carbonic anhydrase II (hCAII) has been investigated. The presence and/or position of a single methyl substituent drastically alters inhibitor potency and can result in coordination modes not observed in small-molecule model complexes. It is shown that this unexpected binding mode is the result of a steric clash between the methyl group and a highly ordered water network in the active site that is further stabilized by the formation of a hydrogen bond and favorable hydrophobic contacts. The affinity of MBPs is dependent on a large number of factors including donor atom identity, orientation, electrostatics, and van der Waals interactions. These results suggest that metal coordination by metalloenzyme inhibitors is a malleable interaction and that it is thus more appropriate to consider the metal-binding motif of these inhibitors as a pharmacophore rather than a "chelator". The rational design of inhibitors targeting metalloenzymes will benefit greatly from a deeper understanding of the interplay between the variety of forces governing the binding of MBPs to active site metal ions.
Departments of Chemistry and Biochemistry, ‡Pharmacology, and §Howard Hughes Medical Institute, University of California, San Diego , 9500 Gilman Drive, MC 0358, La Jolla, California 92093, United States.