4.21 Least-Squares Fitting

There is a simple GUI for this Calculate -> LSQ Superpose...

The scripting interface to LSQ fitting is as follows:

(simple-lsq-match ref-start-resno ref-end-resno ref-chain-id imol-ref mov-start-resno mov-end-resno mov-chain-id imol-mov match-type)

where:

• ref-start-resno is the starting residue number of the reference molecule
• ref-end-resno is the last residue number of the reference molecule
• mov-start-resno is the starting residue number of the moving molecule
• mov-end-resno is the last residue number of the moving molecule
• match-type is one of 'CA, 'main, or 'all.

e.g.: (simple-lsq-match 940 950 "A" 0 940 950 "A" 1 'main)

More sophisticated (match molecule number 1 chain “B” on to molecule number 0 chain “A”):

(define match1 (list 840 850 "A" 440 450 "B" 'all))

(define match2 (list 940 950 "A" 540 550 "B" 'main))

(clear-lsq-matches)

(set-match-element match1)

(set-match-element match2)

(lsq-match 0 1) ; match molecule number 1 onto molecule number 0.