Most reagents that modify side chains are also (not surprisingly) toxic. Many of them are small and therefore membrane-permeable.
Look up recent works on in vivo 'click chemistry'. Unfortunately I doubt that these compounds can be classified as 'cheap'. If you want to do this in vivo, you're probably better off using biology rather than chemistry - i.e. enzyme tagging. If you are able to disclose more details on what are you trying to accomplish perhaps this forum may be of better use :) Artem -----Original Message----- From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Jacob Keller Sent: Thursday, February 21, 2008 5:32 PM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Side chain chemical modifiers Dear Crystallographers, I am looking for a way to modify any specific set of sidechains in my protein (e.g., all K's, or all D's and E's, etc.). A few requirements: 1. Relatively cheap 2. Definitely non-cell-membrane-crossing 3. Specific 4. Any reasonable amount of change in mass (+ 5-5000 Da?), charge, etc., is fine 5. Preferably less life threatening to live cells (I know this is a probably a losing battle) The last criterion is because I want to modify the protein in vivo, then immediately harvest the cells, etc. I was hoping there would be something "around the house" that I could use for this, especially for hitting K's. All the best, Jacob ******************************************* Jacob Pearson Keller Northwestern University Medical Scientist Training Program Dallos Laboratory F. Searle 1-240 2240 Campus Drive Evanston IL 60208 lab: 847.491.2438 cel: 773.608.9185 email: [EMAIL PROTECTED] *******************************************
