[pstricks] How To Begin To Draw This Structure?

[rossi at york.cuny.edu]

Dear Herbert:

Are you able to take a look at Figure 5 in

http://www.bioorganic-chemistry.com/methods.pdf

I want to be able to use pstricks to draw figures like this.

They are very important for RNA research in Chemistry and Biology.

If you were going to do this, what pstricks package would you use?  pschar?
psmatrix?

Please just give a hint in the right direction.

Kind regards,

Angelo