The transcriptional regulator GalR self-assembles to form highly regular tubular structures

TY - JOUR

T1 - The transcriptional regulator GalR self-assembles to form highly regular tubular structures

AU - Agerschou, Emil D

AU - Christiansen, Gunna

AU - Schafer, Nicholas P

AU - Madsen, Daniel Jhaf

AU - Brodersen, Ditlev E

AU - Semsey, Szabolcs

AU - Otzen, Daniel E

PY - 2016

Y1 - 2016

N2 - The Gal repressor regulates transport and metabolism of D-galactose in Escherichia coli and can mediate DNA loop formation by forming a bridge between adjacent or distant sites. GalR forms insoluble aggregates at lower salt concentrations in vitro, which can be solubilized at higher salt concentrations. Here, we investigate the assembly and disassembly of GalR aggregates. We find that a sharp transition from aggregates to soluble species occurs between 200 and 400 mM NaCl, incompatible with a simple salting-in effect. The aggregates are highly ordered rod-like structures, highlighting a remarkable ability for organized self-assembly. Mutant studies reveal that aggregation is dependent on two separate interfaces of GalR. The highly ordered structures dissociate to smaller aggregates in the presence of D-galactose. We propose that these self-assembled structures may constitute galactose-tolerant polymers for chromosome compaction in stationary phase cells, in effect linking self-assembly with regulatory function.

AB - The Gal repressor regulates transport and metabolism of D-galactose in Escherichia coli and can mediate DNA loop formation by forming a bridge between adjacent or distant sites. GalR forms insoluble aggregates at lower salt concentrations in vitro, which can be solubilized at higher salt concentrations. Here, we investigate the assembly and disassembly of GalR aggregates. We find that a sharp transition from aggregates to soluble species occurs between 200 and 400 mM NaCl, incompatible with a simple salting-in effect. The aggregates are highly ordered rod-like structures, highlighting a remarkable ability for organized self-assembly. Mutant studies reveal that aggregation is dependent on two separate interfaces of GalR. The highly ordered structures dissociate to smaller aggregates in the presence of D-galactose. We propose that these self-assembled structures may constitute galactose-tolerant polymers for chromosome compaction in stationary phase cells, in effect linking self-assembly with regulatory function.

U2 - 10.1038/srep27672

DO - 10.1038/srep27672

M3 - Journal article

C2 - 27279285

SN - 2045-2322

VL - 6

JO - Scientific Reports

JF - Scientific Reports

M1 - 27672

ER -