matchmaker doesn't recognize tRNA as Nucleic?

[Elaine Meng]

open 2tra
open 4tra
mm #1 to #2 matrix Nucleic

... gives error message
No chains in reference structure 4tra #2 compatible with Nucleic similarity matrix

The analogous command works with Chimera matchmaker on these 2 structures.

[Eric Pettersen]

Fixed. The wrapping for the C++ function that converts 3-character residue names to the equivalent single character wasn't returning the right type, and therefore the check as to which residues were protein didn't work.