Synthetic crowding agent dextran causes excluded volume interactions exclusively to tracer protein apoazurin.
To understand protein biophysics in crowded cellular environments, researchers often use synthetic polymers as 'crowding agents' in vitro. The idea is that these agents will occupy space and reproduce the in vivo scenario in terms of excluded volume. However, recent work has challenged this concept and pointed out that attractive interactions between protein and crowding agent will provide an enthalpic contribution to the overall effect on protein thermodynamics. Here we use a typical synthetic crowding agent and a well-studied model protein to demonstrate in a window of 50K that the presence of dextran 20 affects apoazurin by steric repulsion.
Department of Chemistry, Umeå University, 90187 Umeå, Sweden.
Alexander
A
Christiansen
Department of Chemistry, Umeå University, 90187 Umeå, Sweden. Electronic address: Pernilla.wittung@chem.umu.se.
Pernilla
P
Wittung-Stafshede
D001059:Apoproteins / Q000737:chemistry*; D001400:Azurin / Q000737:chemistry*; D002942:Circular Dichroism; D003911:Dextrans / Q000737:chemistry*; D011489:Protein Denaturation; D055550:Protein Stability; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa; D013050:Spectrometry, Fluorescence; D044366:Transition Temperature
D001059:Apoproteins; D003911:Dextrans; D001400:Azurin
Attractive interaction; Azurin; Crowding agent; Excluded volume; Macromolecular crowding; Spectroscopy