Re: [ccp4bb] Binding constants/kinetics for crystallisation

2012-12-07 Thread Chittaranjan Das
Roger, Very low values of Kd (nM) may mean that you have a good chance of finding both the proteins (or protein-nucleic acid) together if you get crystals of the mixture. I therefore think that the measurements are useful in that sense. However, low Kd does not necessarily mean that you get

Re: [ccp4bb] seleno methionine labelling of protein

2012-11-12 Thread Chittaranjan Das
Tim, My understanding is that the D-isomer does not get incorporated. I could be wrong though. Bacteria may convert the D to the L-form. Chitta - Original Message - From: Tim Gruene To: CCP4BB@JISCMAIL.AC.UK Sent: Monday, November 12, 2012 4:25:34 AM

Re: [ccp4bb] Intra-molecular interactions

2012-11-03 Thread Chittaranjan Das
Dee, Intramolecular electrostatic interactions are common in protein structures, for example between i and i+4 pairs on the same face of a helix. Robert Baldwin (Stanford) and others did a lot of work on the contribution of intramolecular salt bridges to helix stabilization in model helices.


2012-10-30 Thread Chittaranjan Das
I agree with Garib that we should stop this, because nothing productive seems to be coming out of this discussion. I however like to clarify one thing about the comment I made about agism. I merely intended to interpret what the age limit preference means in the context of Government of

Re: [ccp4bb] oof topic: pH effect on substrate analog

2012-10-30 Thread Chittaranjan Das
Peter, I think it would depend if the substrate analog have ionizable groups? If the analog does not have ionizable groups, it is hard to imagine how the the titration of ionizable groups on the protein would impair the binding. Chitta - Original Message - From: Peter Hsu

Re: [ccp4bb] Ca or Zn

2012-10-30 Thread Chittaranjan Das
Veerendra, You can rule out if zinc has replaced calcium ions (although I agree with Nat and others that looking at the coordination sphere should give a big clue) by taking a few crystals, washing them a couple of times and subjecting them to ICP-MS analysis, if you have access to this

Re: [ccp4bb] Faculty positions at Molecular Biophysics Unit, IISc, Bangalore

2012-10-29 Thread Chittaranjan Das
Please allow me to share with you some history here. Late Prof. GN Ramachandran (of Ramachandran Plot) was a faculty of MBU, IISC. If you want to find out yourself how good/bad it is, please register for the upcoming conference on International Conference on Biomolecular Forms and Functions: