Dear Modellers,

I am having a similar problem as Susan Crennell, whose mail you answered on Nov, 3 . Unfortunately, your advice to correct the alignment does not work in my case. I am trying to model certain loops into an incomplete PDB-file using other PDBs of related proteins as templates for the loops. I used the following top-file:

INCLUDE SET ALNFILE = 'WXY.ali' SET KNOWNS = 'w' 'x' 'y' SET SEQUENCE = 'target' SET ATOM_FILES_DIRECTORY = './' SET STARTING_MODEL= 1 SET ENDING_MODEL = 3

SET OUTPUT_CONTROL = 1 0 1 1 SET MD_LEVEL = 'refine1' SET RSTRS_REFINED = 2

CALL ROUTINE = 'model'

with 3 templates (W, X, Y) and 1 target-sequence (each chain contains ~650 AA), with Y as the incomplete PDB-file, X a different PDB of the same (!) protein and W a related protein.

WXY.ali:

P1;w (structure related to Y and X) structure:w:1::660::::: WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW-WWWWWWWW---WWWWWWW--WWWWWWWWWW* P1;x (same structure as Y, but different pdb-file) structure:x:1::660::::: ------XXXXXXXXX---XXXXXXXXX-XXXX----XXXXXXXXXXX--XXXXXXXXX--XXXXXXXXXXXXXX* P1;y (known structure) structure:y:1::650::::: ------YYYYYYYYY-----YYYYYYYYYY-----YYYYYYYYYYYY--YYYYYYYYY--YYYYYYYYYYYYYY* P1;target (sequence of known structure Y, including missing AA) sequence:target:::::::: ------TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT--TTTTTTTTT--TTTTTTTTTTTTTT*

I called up modeller (Version: mod_iris4d-IRIX5.3) under IRIX6.2 . Approximately 15 min. after the initial model is written, Modeller4 cancels with an error in the log-file:

... getrsr___> Numb of previous, current selected restraints: 56430 68752 mkspline_E> too many parameters, increase MPRMCNS

This error does _not_ occur when there are 5 templates, and 4 of them are identical: SET KNOWNS = 'w' 'y' 'y' 'y' 'y' or 4 templates, and 3 of them are identical (etc...) SET KNOWNS = 'w' 'y' 'y' 'y'

In these cases, I am getting an output with no errors at all, and with a good-looking result, but as soon as I am trying to implement a third template, the described error occurs.

What confuses me is the fact, that when I use just _two_ of these together, there are no problems, no matter which templates I choose: W and X : works (ini-file, restraints-file and schedule-file were written out) Y and X : works (same as above) W and Y : works (same as above); Using all three of them together seems to be impossible. I thought, if there was a problem, then it was because of the slight structure change between Y and X: maybe the difference was big enough to cause problems with the structure of W - but modelling Y by using W and X was possible - no errors !

In a normal log-file, after the selection of the restraints, the SPLINE_RANGE is set; might a change in parameters help, or are there simply to many restraints (using 1*W and 3*Y produces only 25000 restraints, not 68000) ? I tried several other third templates, such as pdb-files that were produced by Modeller4 in previous sessions and that are structurally very close to Y, but then I get the error

addcc2_E> too many parameters, increase MPRMCNS .

I am grateful for any help you can offer me to solve this problem.

Thank you very much in advance,

Thorsten Schweikardt