Are your "affimers" the same as "aptamers"? Can you give me some additional information as to affimers you have developed against common endocrine proteins, and the Kon Koff rates amd how you determined this? Can I evaluate your affimers?
Hi James. This piece on our website discusses the differences between aptamers and Affimers. https://www.avactalifesciences.com/2014/06/20/affimers-are-not-aptamers/. With regard to your other enquiry, we will get in touch by email to discuss your question in more detail. Kind regards.
my wife suffers from autoimmune retinopathy where antibodies are destroyiny her rod and cone cells.she had a serum blood test which showed presence of 70kda protein. could your technology be of help
Hi Joe. Thanks for getting in touch. We will get in touch with you via email. Kind regards.
How about producing affimers specific for red cell antigens or specific for hemoglobin F or S, for diagnostic purposes? What would be the cost?
Hi Helen, thanks for getting in touch. Our customer service team will come back to you shortly. Kind regards.
What kind of Kd's do affimers have? How do they compare to antibodies?
Hi Marc. Affimers have a low molecular weight of 12–14 kDa. Antibodies are much heavier ~150 kDa.
I think Marc asked for an affinity (K(subscript)D, not a molecular weight KDa.
Hi Rob / Marc. We don’t yet routinely measure the Kd of our binders although this will change shortly in the New Year as we are acquiring the methodology to perform high throughput affinity interaction analysis. For the binders that we have measured (using a mixture of ITC, SPR and SPRi), we believe that our current phage display method generates binders that have single to low-double digit disassociation constants. For more information we recommend you download our 'Introduction to Affimers' presentation: https://cdn2.hubspot.net/hub/316126/file-1219202536-pdf/Avacta_Life_Sciences_Presentation.pdf. Many thanks.
You say they are an antibody substitute, compatible with Ab assays. So they bind protein A and can be produced in versions recognized by either anti-mouse or anti-rabbit etc secondary antibodies? Assuming they bind Protein A, is their small size a disadvantage in IPs?
Hi Gregory. The Affimer scaffold is based on the Steffin A protein, it is not recognised by protein A. Affimers are expressed in E. coli and so cannot be recognised by anti-mouse or anti-rabbit antibodies. Instead, we recommend they are detected using an anti-6x His antibody. Our biotinylated Affimers can also be detected using streptavidin-HRP.
How easy is it to chemically modify the affimer, with bi-function linkers, for example? Can they be generated with "spinster" cysteine for maleimide coupling? Can they be generated with on one (or few) lysines to enable NHS-ester coupling at a specific site(s)?
Thanks for your comment Trev. The Affimer scaffold does not contain any cysteine residues so we can generable variants containing a single C-terminal cysteine residue for maleimide coupling. We are also developing double cysteine variants of some of our Affimers. Both of these options allow easy modification of the Affimer molecule and we have had success in using this method for site-specifically biotinylation. We have found that many of our Affimers can be N-terminally biotinylated using NHS-ester coupling under conditions which bias the reaction to the N-terminus without any loss of activity. At this time, our scaffold sequence does contain multiple lysine residues so completely site-specific NHS-ester coupling is not currently possible, but we are continually working on ways to improve our scaffold molecule to give our customers a greater variety of options for Affimer modification.
What is the Tm of range of affimers?
Hi Shawn - Somewhere between 75 and 103oC.
Can affimers be used for detection or treatment of Lymedisease? Whjethro@gmail.com
Can affimers be used for ChIP-seq?
Hi Tom, please could you contact us at firstname.lastname@example.org, or by completing the form here www.avacta.com/contact? We will be able to provide for info to you then.