Isn’t that what the experiment should help you figure out? A could conceivably compete with B-B interactions, leading to A-B heterodimers. A could be so large as to occlude some of its own binding sites on the B hexamer, leading to less than 6 As bound per hexamer of B. Or maybe each A binds two different surfaces of B, such that some number (< or = 6) of As could bridge two B hexamers … or the other way around … Mother Nature is inventive – best to get some experimental numbers!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Phoebe A. Rice Dept. of Biochem & Mol. Biol. and Committee on Microbiology https://voices.uchicago.edu/phoebericelab/ From: CCP4 bulletin board <[email protected]> on behalf of Rezaul Karim <[email protected]> Reply-To: "[email protected]" <[email protected]> Date: Friday, February 21, 2020 at 10:06 AM To: "[email protected]" <[email protected]> Subject: Re: [ccp4bb] ITC Stoichiometry Hi Angshu, Very interesting experiment. Is the B is in hexameric form in solution by itself or it requires A for hexamer formation? Thanks, Reza Md Rezaul Karim PhD candidate PhD Program in Integrated Biomedical Sciences Dept. of Molecular Medicine, Morsani College of Medicine, USF,Tampa Schonbrunn lab, Moffitt Cancer Center, Tampa Email: [email protected], [email protected] Phone: (813) 745 4673 ext. 5462 On Fri, Feb 21, 2020 at 9:59 AM, DUMAS Philippe (IGBMC) <[email protected]> wrote: Dear Angshu The answer to your question requires to define precisely the term of "stoichiometry". *If you consider the hexamer as "the molecule B", then the expected stoichiometric ratio is 1/1 (one molecule A should bind to 1 hexamer B). *But if you consider the monomer of B as "the molecule" in the cell, then the expected stoichiometric ratio is 1/6 (one molecule of A should bind to 6 monomers of the hexamer B). Accordingly, you have to define the concentration in the cell as follows: if you consider the hexamer as "the molecule B" and, let's suppose you have [B] = 10 µM of hexamer, then [B] = 60 µM if you consider the monomer of B as "the molecule". I hope I answered your question. Philippe Dumas ________________________________ De: "Angshu Dutta" <[email protected]> À: "CCP4BB" <[email protected]> Envoyé: Vendredi 21 Février 2020 15:24:53 Objet: [ccp4bb] ITC Stoichiometry Dear all, Apologies for an off-topic question. There are two proteins- A(monomer) and B(hexamer). As per reports, one molecule of A(monomer) should bind to one molecule of B(hexamer). In order to show the interaction between the two proteins through ITC, A is taken in the syringe and B is taken in the cell. What kind of stoichiometry values should be expected? I look forward to your responses. Many thanks in advance. Best, Angshu ________________________________ 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 ________________________________ 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
