Distinct features of protein folding by the GroEL system from a psychrophilic bacterium, Colwellia psychrerythraea 34H

Abstract

We investigated the protein folding mechanism of the GroEL system of a psychrophilic bacterium, Colwellia psychrerythraea 34H. The amount of mRNA of the groESL operon of C. psychrerythraea was increased about 6-fold after a temperature upshift from 8 to 18 °C for 30 min, suggesting that this temperature causes heat stress in this bacterium. A σ(32)-type promoter was found upstream of the groESL, suggesting that the C. psychrerythraea groESL is regulated by the σ(32) system, like the groESL in E. coli. The maximum ATPase and CTPase activities of CpGroEL were observed at 45 and 35 °C, respectively, which are much higher than the growth temperatures of C. psychrerythraea. We found that the refolding activity of the CpGroEL system in the presence of ATP is lower than that in the presence of CTP. This suggests that ATP is not the optimum energy source of the CpGroEL system. Analyses for the interaction of CpGroEL-CpGroES revealed that CTP could weaken this interaction, resulting in effective refolding function of the CpGroEL system. From these findings, we consider that the CpGroEL system possesses an energy-saving mechanism for avoiding excess consumption of ATP to ensure growth in a low-temperature environment.

Colwellia psychrerythraea Strains from Distant Deep Sea Basins Show Adaptation to Local Conditions

“…C. psychrerythraea is a model psychrophilic heterotroph and much of our understanding of the adaptations for microbial growth in cold environments comes from studies performed on C. psychrerythraea 34H (Junge et al, 2003;Methé et al, 2005;Casanueva et al, 2010;Yamauchi et al, 2012). In the present study, phenotypic comparison was performed using the Biolog high-throughput Phenotype MicroArray system to assess carbon source utilization and salt tolerance.…”

Model metabolic strategy for heterotrophic bacteria in the cold ocean based on Colwellia psychrerythraea 34H

“…Able to grow at temperatures as low as −12°C (19), 34H has been used to study cold-adapted proteins (20) and enzymes (21), extracellular polysaccharide substances (18,22), and motility and chemohalotaxis at subzero temperatures (23,24). Recently, investigation of cold-adapted enzymes has increased in importance due to the potential economic and ecological advantages they can provide over their higher-temperature-requiring counterparts in industrial processes (25).…”

A novel mechanism of “metal gel-shift” by histidine-rich Ni2+-binding Hpn protein from Helicobacter pylori strain SS1

“…Recombinant Hpn was purified from harvested cells of 200 ml culture. Harvested cells were suspended in lysis buffer (50 mM Tris-HCl, pH 7.5, and 500 mM NaCl) and purification was done as described previously for His-tagged proteins with some modifications [ 38 ]. After sonication (TOMY Ultrasonic Disruptor, duty: 50, output: 4, time: 4 min x 6), supernatant fractions were filtered using Millex ® GV filter units of 0.22-μm-pore-size and applied onto a 1-ml HiTrap chelating column (GE Healthcare) that had been equilibrated with start buffer containing 20 mM imidazole, 50 mM Tris-HCl, and 500 mM NaCl.…”