sino biological 40150 mm02  (Sino Biological)

Journal: Nucleic Acids Research

Article Title: A general strategy to enhance aptamer affinity by suppressing dissociation through symmetric assembly

doi: 10.1093/nar/gkag268

Figure Lengend Snippet: Symmetric aptamer trimerization enhances binding affinity. ( A ) Schematic illustration of aptamer assembly. The 3′ end of monomeric aptamer MSA52t was linked to the trident linker (trebler phosphoramidite) with a 15-thymidine spacer (T15) and assembled into dimeric (shDMSA52t) or trimeric (shTMSA52t) constructs. This design provides flexible orientation and optimal target accessibility for each aptamer unit. ( B ) Dot-blot binding assays showing the affinities of MSA52t, shDMSA52t, and shTMSA52t toward the monomeric wild-type S-protein (mS-protein). Apparent dissociation constants ( K d ) were determined by nonlinear curve fitting. Trimeric assembly resulted in a ∼344-fold affinity enhancement over the monomer.

Article Snippet: The wild-type SARS-CoV-2 spike protein subunit S1 (mS-protein, Cat. No. 40591-V08B1) and Troponin I (Cat. No. 501-TNNI0010) were purchased from Sino Biological Inc. VEGF 165 protein (his-tagged, Cat. No. VE5-H5248) was obtained from Acro Biosystems.

Techniques: Binding Assay, Construct, Dot Blot

Journal: Nucleic Acids Research

Article Title: A general strategy to enhance aptamer affinity by suppressing dissociation through symmetric assembly

doi: 10.1093/nar/gkag268

Figure Lengend Snippet: Trimeric assembly enhances affinity primarily by reducing dissociation rate. Binding kinetics of ( A ) MSA52t, ( B ) shDMSA52t, and ( C ) shTMSA52t interacting with the wild-type SARS-CoV-2 S1-protein (mS-protein) were measured by BLI. Concentration-dependent sensorgrams were globally fitted using 1:1 binding model to obtain the kinetic parameters k on , k off , and K d . The experimental curves are shown as solid lines and the fitted curves are shown as black dashed lines. Bar graphs comparing ( D ) k on , ( E ) k off , and ( F ) K d values for each aptamer. While only modest changes in k on were observed, trimerization led to a dramatic reduction in k off , resulting in a 348-fold improvement in K d for shTMSA52t compared to the monomer.

Article Snippet: The wild-type SARS-CoV-2 spike protein subunit S1 (mS-protein, Cat. No. 40591-V08B1) and Troponin I (Cat. No. 501-TNNI0010) were purchased from Sino Biological Inc. VEGF 165 protein (his-tagged, Cat. No. VE5-H5248) was obtained from Acro Biosystems.

Techniques: Binding Assay, Concentration Assay