Recently, the atomic structures of the large ribosomal subunit from Haloarcula marismortui and its complexes with substrates have been determined. These have provided exciting new insights into the principles of RNA structure, the mechanism of the peptidyl-transferase reaction and early events in the evolution of this RNA-protein complex assembly that is essential in all cells. The structures o...

Water-biomolecule interactions have been extensively studied in dilute solutions, crystals, and rehydrated powders, but none of these model systems may capture the behavior of water in the highly organized intracellular milieu. Because of the experimental difficulty of selectively probing the structure and dynamics of water in intact cells, radically different views about the properties of cell...

Ribosomes are universal translators of the genetic code into protein and represent macromolecular structures that are asymmetric, often heterogeneous, and contain dynamic regions. These properties pose considerable challenges for modern-day structural biology. Despite these obstacles, high-resolution x-ray structures of the 30S and 50S subunits have revealed the RNA architecture and its interac...

We describe a method to establish chronologies of ancient ribosomal evolution. The method uses structure-based and sequence-based comparison of the large subunits (LSUs) of Haloarcula marismortui and Thermus thermophilus. These are the highest resolution ribosome structures available and represent disparate regions of the evolutionary tree. We have sectioned the superimposed LSUs into concentri...

We develop novel methods for recognizing and cataloging conformational states of RNA, and for discovering statistical rules governing those states. We focus on the conformation of the large ribosomal subunit from Haloarcula marismortui. The two approaches described here involve torsion matching and binning. Torsion matching is a pattern-recognition code which finds structural repetitions. Binni...

Although many haloarchaea produce biodegradable polyhydroxyalkanoates (PHAs), the genes involved in PHA synthesis in the domain of Archaea have not yet been experimentally investigated yet. In this study, we revealed that Haloarcula marismortui was able to accumulate poly(3-hydroxybutyrate) (PHB) up to 21% of cellular dry weight when cultured in a minimal medium with excessive glucose and ident...

Haloarchaea that inhabit Great Salt Lake (GSL), a thalassohaline terminal lake, must respond to the fluctuating climate conditions of the elevated desert of Utah. We investigated how shifting environmental factors, specifically salinity and temperature, affected gene expression in the GSL haloarchaea, NA6-27, which we isolated from the hypersaline north arm of the lake. Combined data from culti...

Bacteriorhodopsins are a large family of seven-helical transmembrane proteins that function as light-driven proton pumps. Here, we present the crystal structure of a new member of the family, Haloarcula marismortui bacteriorhodopsin I (HmBRI) D94N mutant, at the resolution of 2.5 Å. While the HmBRI retinal-binding pocket and proton donor site are similar to those of other archaeal proton pumps,...

Crystal structures of the 50 S ribosomal subunit from Haloarcula marismortui complexed with two antibiotics have identified new sites at which antibiotics interact with the ribosome and inhibit protein synthesis. 13-Deoxytedanolide binds to the E site of the 50 S subunit at the same location as the CCA of tRNA, and thus appears to inhibit protein synthesis by competing with deacylated tRNAs for...