My guess would be that the chains were prepared under reducing conditions, mixed, and then allowed to oxidize. The surface adduct could easily form during this process.
On Mar 27, 2020, at 4:38 PM, Cowan, Richard H. (Dr.) <[email protected]<mailto:[email protected]>> wrote: Hi, The Fab constructs have a c-terminal cysteines on both the heavy and light chains, which should form a disulphide. Adding reducing agent to the purification of the protein would potentially reduce this disulphide, possible causing issues the stability and heterogeneity? At least that's my understanding? Thanks, Dr Richard Cowan Research Associate HWLSB 1/05 Department of Biochemistry University of Leicester Lancaster Road Leicester, LE1 9HN, U.K. Phone +44 (0) 116 229 7077 ________________________________ From: CCP4 bulletin board <[email protected]<mailto:[email protected]>> on behalf of Paul Emsley <[email protected]<mailto:[email protected]>> Sent: 27 March 2020 21:33 To: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>> Subject: Re: [ccp4bb] Covalent Cysteine Aduct On 27/03/2020 21:06, Cowan, Richard H. (Dr.) wrote: although [BME] seems unlikely, since the crystallized protein is a Fab. I don't follow. ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1<https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jiscmail.ac.uk%2Fcgi-bin%2Fwebadmin%3FSUBED1%3DCCP4BB%26A%3D1&data=02%7C01%7Crc273%40leicester.ac.uk%7Cefd3063762a94fa1082708d7d29693a6%7Caebecd6a31d44b0195ce8274afe853d9%7C0%7C0%7C637209416466926320&sdata=BB7rIfkFGYrsbhD2G2fg%2FfWmNwb0BPo2fNNFrkaCttE%3D&reserved=0> ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
