Re: [ccp4bb] extra Fo-Fc density in two Cysteines

We have seen quite a few of these. Oxidation of S. Mostly in our case a result if reaction with beta-mercaptoethanol.. Jan On Mon, Dec 18, 2023 at 6:14 PM Liliana Margent < lmarg...@gradcenter.cuny.edu> wrote: > Hi there, We’ve been having an issue in trying to clear regions of Fo-Fc > density

Re: [ccp4bb] extra Fo-Fc density in two Cysteines

Hello, you seem to have positive difference density for the Cys sulphur/sulfur atom. It would be worth checking it's occupancy. Best wishes, Jon Cooper. jon.b.coo...@protonmail.com Sent from Proton Mail mobile Original Message On 18 Dec 2023, 17:03, Liliana Margent wrote: > H

Re: [ccp4bb] extra Fo-Fc density in two Cysteines

, Forest E, Arlaud G, Seigneurin JM, Ruigrok RW, Burmeister WP. J Mol Biol. 2002 Nov 15;324(1):89-103. doi: 10.1016/s0022-2836(02)01040-9. Wim De: "Liliana Margent" À: "CCP4BB" Envoyé: Lundi 18 Décembre 2023 18:03:46 Objet: [ccp4bb] extra Fo-Fc density in two Cystein

Re: [ccp4bb] extra Fo-Fc density in two Cysteines

Difficult to be sure from a single angle pic but I would suggest Cys oxidation. There is an important 20 years old paper (see below) on Cys oxidation in a tyrosine phosphatase (like yours) Best Roberti] Nature *

Re: [ccp4bb] extra Fo-Fc density in two Cysteines

Hi Liliana, May be it would be good to know if this adduct was formed during crystallization or protein was modified prior to crystallization. One could consider performing a protease digestion, followed by LC-MS/MS to determine the molecular weight of the adduct and then work backwards to account