Hi,
a likely scenario is that your mutant crystallises in the same
conformation/packing as the wild-type protein, and this conformation is good
for ligand binding. In solution, your mutant protein may be more flexible/open
than the wild-type and affinity hence lower. We see this quite often. Var
panchal
Sent: Saturday, February 22, 2020 3:25 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Contradictory result between ITC and cocrystal structure
Hi Monika,
If the protein cocrystalize with ligand doesn't mean it interacts with protein.
You have provided insufficient information
panchal
Sent: Saturday, February 22, 2020 3:25 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Contradictory result between ITC and cocrystal structure
Hi Monika,
If the protein cocrystalize with ligand doesn't mean it interacts with protein.
You have provided insufficient information
help.
Regards,
Dhabaleswar Patra
Purdue University, IN
From: CCP4 bulletin board on behalf of vipul panchal
Sent: Saturday, February 22, 2020 4:25 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Contradictory result between ITC and cocrystal structure
Hi Monika,
Hi Monika,
If the protein cocrystalize with ligand doesn't mean it interacts with
protein.
You have provided insufficient information here. Does the ligand is bound
to mutant protein with atleast 2 or 3 hydrogen bonds (how many residues are
mutated?) ? If no that means, it is just cocrystalizing b
Beside no change in enthalpy, was there no change in the entropy and
affinity?
Pankaj Kumar Chauhan, PhD
Assistant Professor
Ramalingaswami Fellow
Department of Biochemistry
Jamia Hamdard University (Institute of Eminence by Govt. of India)
Hamdard Nagar, Delhi, India 110062
Skype: pankajimtech
P
Dear Monika,
Did you do the proper positive and -ve control for ITC.
It is impossible that there are no changes in thermodynamics.. when it
binds..
Either your detector is not sensing it OR your experiment is not running
properly..
HTH
Best wishes,
Natesh
On Sat, 22 Feb 2020 at 12:01, monika chand
Dear All,
I have a situation, where a mutant protein does not exhibit
any heat change upon titration with cognate ligand in the ITC experiment.
However, it co-crystallizes with the respective cognate ligand. Also, the
cocrystal structure reveals the conservation of the hydrogen bondi
