INDEX subunit structure

The coupling factor has the subunit structure 03/33766 where a-e denote the type of subunit and the index the corresponding stoichiometrical number. 

For molecular connectivity indices with orders higher than 2, it is also necessary to specify the subclass of index. There are four subclasses of higher order indices path, cluster, path/cluster, and chain. These subclasses are defined by the type of structural subunits they are describing, a subunit over which the summation is to be taken when the respective indices are calculated. Naturally, the valence counterparts of all four subclasses of higher order indices can be easily defined by analogy, described above for the first-order valence molecular connectivity index. 

Histone database RNA structure database RNA modification database European large subunit rRNA database http //genome.nhgri.nih.gov/histones/ http // mabase.org http //medlib.med.utah.edu/RNAmods http //rma.uia.ac.be/lsu/index.html... 

---