Structural descriptors hydrogen-bonding donor atoms

The descriptor uses readily calculable physicochemical properties from the topological structure. The descriptors used in this study were atomic weight, hydropho-bicity, molecular refractivity, atomic charge, polar surface area, hydrogen bond acceptors, and hydrogen bond donors. The authors note that Martin et al. [32] applied a similar approach for the design of diverse combinatorial libraries. 

In actual applications of MSA, many different types of representations are utilized to compute molecular similarities [41, 52-54]. Johnson [55] has provided a detailed discussion of the manifold types of mathematical spaces and their associated representations. The information contained in the representations is usually in the form of molecular or chemical features called descriptors that are derived from the structural and chemical properties of molecules. Descriptors ate nominally classified as ID (one-dimensional), 2D, or 3D. ID descriptors are usually associated with whole molecule properties such as molecular weight, logP, solubility, number of hydrogen bond donors, nnmber of rotatable bonds, and so on. 2D descriptors are associated with the topological strnctnre of molecules as typically depicted in chemists drawings. Such depictions show the atoms, the bonds connecting them, and in some cases include stereochemical features, but they do not explicitly depict the 3D structures of molecules. 3D descriptors, as their name implies, are associated with the 3D structures of molecules. Todeschini and Consonni [56] have compiled an extensive reference containing many of the descriptors used in chemical informatics applications. 

---