[modeller_usage] toppar files for Charmm and X-plor

Dear Modellers,

Topology and parameter files for compounds are relatively easy to find for X-plor format rather than for Charmm format that is used for the Modeller program in the websites. What are the major differences of the files between X-plor format and Charmm format? Is there an easy way to convert the X-plor format to the Charmm format?

Cheers, Han