Dear all

Thanks for all the advice and suggestions.

After multiple attempts I believe we were actually building too many residues to the N-terminus (!). It also appeared the region is complicated by extra density (seems to be EDO, likely degraded from PEG), which were mis-treated as protein. Deleting the nearby mis-placed residues allowed the green blobs to be fitted.

Thanks again!

Sam




On Mon, 29 Apr 2019 at 20:08, Grüne Tim (PSI) <Tim.Gruene@psi.ch> wrote:
Dear Sam,

at 1.5A you might expect to see holes in the aromatic rings and at least a den in the proline residue.
The region of your screen shot is quite noisy - either you integrated your data too far into the noise, or there is more than one conformation of the side chain. You can split the range of offending residues, including 1-2 either side, and see if coot models the second one reasonably.

Best,
Tim
From: phenixbb-bounces@phenix-online.org [phenixbb-bounces@phenix-online.org] on behalf of Sam Tang [samtys0910@gmail.com]
Sent: Friday, April 26, 2019 2:38 PM
To: PHENIX user mailing list
Subject: [phenixbb] modelling into positive densities

Hello,

I am refining a structure solved to 1.5A by MR. Rw/Rf were 0.17/0.22 which seem acceptable to me. At the very beginning part of the protein the electron density is a bit wobbly. I am able to build the residues into the positive densities. But after phenix.refine the chain always shifts away a bit and leaves the green blobs there. 


I am thinking if this can be solved by adjusting the target weights. Or can I apply certain restraints only to those few residues?

I refined XYZ (reciprocal space), XYZ (real space), individual B-factors, TLS and occupancies.

Thanks in advance.

Regards

Sam