Ca Cb chemical shifts as restraints
Ricard A. Rodriguez
rarodrig at qo.ub.es
Mon Dec 3 12:18:50 EST 2001
I'm quite new using CNS. I've been trying to obtain a low resolution structure
for a 20 kD protein. I've encountered some problems when including, Ca and
Cb chemical shifts as restraints for the CNS calculation.
The input file seems to be correct, but in the generated structures nearly all
restraints are violated. Also in the output i get the next message for most
of the residues:
The following Ca or Cb delta secondary
shifts are greater than the cutoff (-99.99 = no expectation):
(Ca) (obsCa) (rcoilCa) (obsdeltaCa) (calcdeltaCa) (deltadeltaCa)
(obsCb) (rcoilCb) (obsdeltaCb) (calcdeltaCb) (deltadeltaCb)
8 GLU CA 55.00 56.40 -1.40-99.99-99.99 33.68 29.70 3.98-99.99-99.99
9 GLN CA 57.50 56.10 1.40-99.99-99.99 29.19 28.40 0.79-99.99-99.99
it seems that the program doesnt read well the random coil values from the
libraries, but anyway i dont know how to solve it.
If anyone has the answer i'd be very grateful.
Thanks in advance.
Ricard A. Rodríguez
Dept. Química Orgànica (Unitat 10)
Universitat de Barcelona
C/ Martí i Franqués 1-11
email: rarodrig at qo.ub.es
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