Macromolecular crowding increases structural content of folded proteins.
Here we show that increased amount of secondary structure is acquired in the folded states of two structurally-different proteins (alpha-helical VlsE and alpha/beta flavodoxin) in the presence of macromolecular crowding agents. The structural content of flavodoxin and VlsE is enhanced by 33% and 70%, respectively, in 400 mg/ml Ficoll 70 (pH 7, 20 degrees C) and correlates with higher protein-thermal stability. In the same Ficoll range, there are only small effects on the unfolded-state structures of the proteins. This is the first in vitro assessment of crowding effects on the native-state structures at physiological conditions. Our findings imply that for proteins with low intrinsic stability, the functional structures in vivo may differ from those observed in dilute buffers.
Perham
Michael
M
Department of Chemistry, Rice University, 6100 Main Street, Houston, TX 77251, USA.
Stagg
Loren
L
Wittung-Stafshede
Pernilla
P
D000942:Antigens, Bacterial / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D045285:Desulfovibrio desulfuricans / Q000378:metabolism; D005362:Ficoll / Q000737:chemistry; D005418:Flavodoxin / Q000737:chemistry*; D006358:Hot Temperature; D008074:Lipoproteins / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D005418:Flavodoxin; D008074:Lipoproteins; C105546:VlsE protein, Borrelia burgdorferi; D005362:Ficoll