Looking for software for distance plot

[Dr. B. K. Sathyanarayana]

	I am looking for a software that gives contoured distance
	plot for C-alpha atoms. As it is known this is symmetrical
	about the diagonal with x and y axis being the residue 
	numbers. This is also used for identifying domains in
	proteins. (Ref: Principles of Protein Structures by
	Schulz and Schirmer, page 147)

	thanks
	sathya


-- 
B.K. Sathya
National Cancer Institute
Frederick, Maryland
sathya at ncifcrf.gov