Abstract
Protein‐surface interactions are exploited in various processes in life sciences and biotechnology. Many of such processes are performed in presence of a buffer system, which is generally believed to have an influence on the protein‐surface interaction but is rarely investigated systematically. Combining experimental and theoretical methodologies, we herein demonstrate the strong influence of the buffer type on protein‐surface interactions. Using state of the art chromatographic experiments, we measure the interaction between individual amino acids and silica, as a reference to understand protein‐surface interactions. Among all the 20 proteinogenic amino acids studied, we found that arginine (R) and lysine (K) bind most strongly to silica, a finding validated by free energy calculations. We further measured the binding of R and K at different pH in presence of two different buffers, MOPS (3‐(N‐morpholino)propanesulfonic acid) and TRIS (tris(hydroxymethyl)aminomethane), and find dramatically different behavior. In presence of TRIS, the binding affinity of R/K increases with pH, whereas we observe an opposite trend for MOPS. These results can be understood using a multiscale modelling framework combining molecular dynamics simulation and Langmuir adsorption model. The modelling approach helps to optimize buffer conditions in various fields like biosensors, drug delivery or bio separation engineering prior to the experiment.
Highlights
The modelling approach helps to optimize buffer conditions in various fields like biosensors, drug delivery or bio separation engineering prior to the experiment
We could show the capability of chromatography for studying interactions between single amino acids (AAs) and silica surfaces under different conditions in aqueous systems
Chromatography has the advantage of real time monitoring and the possibility to have an automated high throughput system, which leads to a lot of data points with little effort
Summary
We first measured the interactions between AAs and silica solid phase in a chromatographic system in aqueous buffered solution (Figure 1a). The driving force for interaction of AAs with silica are the additional basic groups in R and K[32] which provide strong electrostatic interactions with silica at high pH.[37] It is important to note that in Figure 1 the experimental results are from the 10 mM TRIS pH 8 run and the simulation is in water. This is due to the problem, that in plain water the basic amino acids show high adsorption and no measurable retention time. This effect is mainly due to the competitive effect of TRIS on the AA adsorption and will be discussed in greater detail in the section below
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
