Re: [ccp4bb] homology modeling----good bond lengths, bad angles

2007-02-28 Thread Leo Chavas

Dear Anagha,

just a guess...

I'm not sure I understood you properly, but you are only trying to  
make a model of a solved protein which will lack 3-4 amino acids in a  
loop... therefore, why not using a modeling soft, such as Coot,  
remove the amino acids, and do one run of "Regularize Zone"?? You  
might need to renumber your chain once you have removed the amino  
acids, but it might work...


just a guess...

Best regards.
Leo


On Mar 1, 2007, at 4:11 AM, anagha gupta wrote:


Hi CCP4 community!

I have constructed a homology model of a deletion variant of a  
protein whose structure has already been solved.  These deletions  
are 3-4 amino acid in length and are in a loop that connects two  
helices.  The model structures look good with respect to bond  
lengths in the aforementioned loop region but the bond angles  
(especially Phi and Psi) are very distorted.  Ramachandran plot  
suggests the same and some of the amino acids flanking the loop are  
now in the disallowed region.
I thought one way to avoid this is to delete one amino acid at a  
time and construct the model and use the previous model as the  
template to construct the next model.  This is not working very  
well in fixing the wrong angles.


I was wondering if

1) Anybody out there knows good homology modeling software.  I used  
SWISS model and CPH model to create my models. I have heard about  
prime but right now am waiting to get the software .
2) Is there a way I can fix the angles if I perform an energy  
minimization of the model.


Suggestions are appreciated.
Thanks,
Anagha.


==
Chavas Leonard M.G., Ph.D.
Structural Research Center
KEK,PF. 1-1 Oho
Tuskuba, Ibaraki - Japan
-
PHS: +81(0)29-864-5200 (ext: 2682)
e-mail: [EMAIL PROTECTED]
URL: http://pfweis.kek.jp/~leo
==



Re: [ccp4bb] homology modeling----good bond lengths, bad angles

2007-02-28 Thread Sudharsan Sridharan

Have you tried Modeller ?
-Sid.

On 2/28/07, anagha gupta <[EMAIL PROTECTED]> wrote:

Hi CCP4 community!

I have constructed a homology model of a deletion variant of a protein whose
structure has already been solved.  These deletions are 3-4 amino acid in
length and are in a loop that connects two helices.  The model structures
look good with respect to bond lengths in the aforementioned loop region but
the bond angles (especially Phi and Psi) are very distorted.  Ramachandran
plot suggests the same and some of the amino acids flanking the loop are now
in the disallowed region.
I thought one way to avoid this is to delete one amino acid at a time and
construct the model and use the previous model as the template to construct
the next model.  This is not working very well in fixing the wrong angles.

I was wondering if

1) Anybody out there knows good homology modeling software.  I used SWISS
model and CPH model to create my models. I have heard about prime but right
now am waiting to get the software .
2) Is there a way I can fix the angles if I perform an energy minimization
of the model.

Suggestions are appreciated.
Thanks,
Anagha.


[ccp4bb] homology modeling----good bond lengths, bad angles

2007-02-28 Thread anagha gupta

Hi CCP4 community!

I have constructed a homology model of a deletion variant of a protein whose
structure has already been solved.  These deletions are 3-4 amino acid in
length and are in a loop that connects two helices.  The model structures
look good with respect to bond lengths in the aforementioned loop region but
the bond angles (especially Phi and Psi) are very distorted.  Ramachandran
plot suggests the same and some of the amino acids flanking the loop are now
in the disallowed region.
I thought one way to avoid this is to delete one amino acid at a time and
construct the model and use the previous model as the template to construct
the next model.  This is not working very well in fixing the wrong angles.

I was wondering if

1) Anybody out there knows good homology modeling software.  I used SWISS
model and CPH model to create my models. I have heard about prime but right
now am waiting to get the software .
2) Is there a way I can fix the angles if I perform an energy minimization
of the model.

Suggestions are appreciated.
Thanks,
Anagha.