Hi Jon there is no surface exposed cysteine nearby which can potentially make disulfide bond with the modified cysteine intramolecularily.
Dhiraj ________________________________ From: Jon Cooper <jon.b.coo...@protonmail.com> Sent: Sunday, November 1, 2020 7:41 AM To: Srivastava, Dhiraj <dhiraj-srivast...@uiowa.edu>; CCP4BB@JISCMAIL.AC.UK <CCP4BB@JISCMAIL.AC.UK> Subject: Re: [ccp4bb] Cysteine oxidation product Hello, does the protein you added cysteine to (I assume you mean by mutagenesis) have another cysteine which could make an intra molecular disulphide with it? That would probably not show on non-reducing SDS? Best wishes, Jon Cooper -------- Original Message -------- On 31 Oct 2020, 15:58, Srivastava, Dhiraj < dhiraj-srivast...@uiowa.edu> wrote: Hi All I added an extra cysteine residue to one of my protein interactions partners and somehow it increased the affinity in the absence of reducing agent however in the presence of reducing agent, the affinity is same. there is no disulfide bond formation between the two interaction partner as in non-reducing SDS-PAGE, I see the molecular weights corresponding to only the individual proteins and not the sum of two. Does anyone has ever seen this? at pH 8.0, what is the probability that a surface exposed cysteine will have a net negative charge and still not very reactive? can it exist as thiolate, sulfinate or sulfonate ion? is there any such example in literature that anyone knows? Thank you Dhiraj ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/