Genetic engineering of a novel protein-nanoparticle hybrid system with great potential for biosensing applications and for patterning of various types of nanoparticles is described. The hybrid system is based on a genetically modified chaperonin protein from the hyperthermophilic archaeon Sulfolobus shibatae. This chaperonin is an 18-subunit double ring, which self-assembles in the presence of Mg ions and ATP.
View Article and Find Full Text PDFSelf-assembling biomolecules that form highly ordered structures have attracted interest as potential alternatives to conventional lithographic processes for patterning materials. Here, we introduce a general technique for patterning nanoparticle arrays using two-dimensional crystals of genetically modified hollow protein structures called chaperonins. Constrained chemical synthesis of transition metal nanoparticles is initiated using templates functionalized with polyhistidine sequences.
View Article and Find Full Text PDFThe possibility of an ocean within the icy shell of Jupiter's moon Europa has established that world as a primary candidate in the search for extraterrestrial life within our Solar System. This paper evaluates the potential to detect evidence for microbial life by comparing laboratory studies of terrestrial microorganisms with measurements from the Galileo Near Infrared Imaging Spectrometer (NIMS). If the interior of Europa at one time harbored life, some evidence may remain in the surface materials.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2003
Chaperonins are protein complexes that are believed to function as part of a protein folding system in the cytoplasm of the cell. We observed, however, that the group II chaperonins known as rosettasomes in the hyperthermophilic archaeon Sulfolobus shibatae, are not cytoplasmic but membrane associated. This association was observed in cultures grown at 60 degrees C and 76 degrees C or heat-shocked at 85 degrees C by using immunofluorescence microscopy and in thick sections of rapidly frozen cells grown at 76 degrees C by using immunogold electron microscopy.
View Article and Find Full Text PDFThe hyperthermoacidophilic archaeon Sulfolobus shibatae contains group II chaperonins, known as rosettasomes, which are two nine-membered rings composed of three different 60 kDa subunits (TF55 alpha, beta and gamma). We sequenced the gene for the gamma subunit and studied the temperature-dependent changes in alpha, beta and gamma expression, their association into rosettasomes and their phylogenetic relationships. Alpha and beta gene expression was increased by heat shock (30 min, 86 degrees C) and decreased by cold shock (30 min, 60 degrees C).
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