Subunit a of the Escherichia coli ATP synthase, a 30 kDa integral membrane protein, was purified to homogeneity by a novel procedure incorporating selective extraction into a monophasic mixture of chloroform, methanol and water, followed by Ni-NTA chromatography in the mixed solvent. Pure subunit a was reconstituted with subunits b and c and phospholipids to form a functional proton-translocating unit. Nuclear magnetic resonance (NMR) spectra of the pure subunit a in the mixed solvent show good chemical shift dispersion and demonstrate the potential of the solvent mixture for NMR studies of the large membrane proteins that are currently intractable in aqueous detergent solutions.
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http://dx.doi.org/10.1016/s0014-5793(03)01360-7 | DOI Listing |
Proc Natl Acad Sci U S A
February 2025
Laboratory of Molecular Biology, National Cancer Institute, NIH, Bethesda, MD 20892.
Hsp70, Hsp90, and ClpB/Hsp100 are molecular chaperones that help regulate proteostasis. Bacterial and yeast Hsp70s and their cochaperones function synergistically with Hsp90s to reactivate inactive and aggregated proteins by a mechanism that requires a direct interaction between Hsp90 and Hsp70 both in vitro and in vivo. and yeast Hsp70s also collaborate in bichaperone systems with ClpB and Hsp104, respectively, to disaggregate and reactivate aggregated proteins and amyloids such as prions.
View Article and Find Full Text PDFExtremophiles
January 2025
Microbiology Laboratory, Department of Botany (DST-FIST and UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal, 731235, India.
To fish-out novel salt-tolerance genes, metagenomic DNA of moderately saline sediments of India's largest hypersaline Sambhar Lake was cloned in fosmid. Two functionally-picked clones helped the Escherichia coli host to tolerate 0.6 M NaCl.
View Article and Find Full Text PDFNat Commun
January 2025
Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.
Recalcitrant bacterial infections can be caused by various types of dormant bacteria, including persisters and viable but nonculturable (VBNC) cells. Despite their clinical importance, we know fairly little about bacterial dormancy development and recovery. Previously, we established a correlation between protein aggregation and dormancy in Escherichia coli.
View Article and Find Full Text PDFBiophys J
January 2025
Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama. Electronic address:
The Hsp100 family of protein disaggregases play important roles in maintaining protein homeostasis in cells. E. coli ClpB is an Hsp100 protein that solubilizes protein aggregates.
View Article and Find Full Text PDFBiochemistry
January 2025
Department of Chemistry and Biochemistry, San Francisco State University, 1600 Holloway Avenue, San Francisco, California 94132, United States.
Glutamine synthetase (GS) is a ubiquitous enzyme central to nitrogen metabolism, catalyzing the ATP-dependent formation of glutamine from glutamate and ammonia. Positioned at the intersection of nitrogen metabolism with carbon metabolism, the activity of GS is subject to sophisticated regulation. While the intricate regulatory pathways that govern GS were established long ago, recent work has demonstrated that homologues are controlled by multiple distinct regulatory patterns, such as the metabolite induced oligomeric state formation in archaeal GS by 2-oxoglutarate.
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