We describe genetic engineering of a novel protein-nanoparticle hybrid system with great potential for patterning of
various types of nanoparticles and for biosensing applications. 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. We describe a chaperonin mutant (His-β-
loopless:HBLL), with increased access to the central cavity and His-tags on each subunit extending into the central
cavity. This mutant binds water-soluble semiconductor quantum dots, creating a protein-encapsulated fluorescent
nanoparticle. By adding selective binding sites to the solvent-exposed regions of the chaperonin, this proteinnanoparticle
bioconjugate becomes a sensor for specific targets. Using a combination of biochemical and spectroscopic
assays, we characterize the formation, stoichiometry, affinity and stability of these novel sensors.
As the nano-scale becomes a focus for engineering electronic, photonic, medical, and other important devices, an
unprecedented role for biomolecules is emerging to address one of the most formidable problems in nano-manufacturing:
precise manipulation and organization of matter on the nano-scale. Biomolecules are a solution to this problem because
they themselves are nanoscale particles with intrinsic properties that allow them to precisely self-assemble and self-organize
into the amazing diversity of structures observed in nature. Indeed, there is ample evidence that the combination
of molecular recognition and self-assembly combined with mutation, selection, and replication have the potential to
create structures that could truly revolutionize manufacturing processes in many sectors of industry. Genetically
engineered biomolecules are already being used to make the next generation of nano-scale templates, nano-detailed
masks, and molecular scaffolds for the future manufacturing of electronic devices, medical diagnostic tools, and
chemical engineering interfaces. Here we present an example of this type of technology by showing how a protein can be
genetically modified to form a new structure and coated with metal to lead the way to producing "nano-wires," which
may ultimately become the basis for self-assembled circuitry.
In this paper we describe "extremophiles" and "survivophiles" and consider their role in the continuity and perpetuity of life throughout Earth's turbulent history. The term "extremophiles" refers to organisms active in what are considered by human beings to be extreme physical or chemical environments. The term "survivophiles" collectively refers to organisms capable of assuming reversible inactive states (suspended or latent), which enable them to survive harsh conditions until what they consider hospitable conditions to metabolic activity return. We present the various biological states of individual organisms (active, inactive, transition) and how these states relate to the dynamic biological-physicalchemical context that makes up an organism's environment. We argue that within these states the special adaptations of extremophiles and survivophiles have allowed life as a phenomenon to withstand global catastrophes, which include massive volcanic eruptions, supernovae explosions, and asteroid impacts. These are the catastrophes that changed the environments on Earth too quickly for organisms to adapt by Darwinian evolution. We suggest that genetic adaptations of extremophiles both allow them to thrive under at least some of the harsh conditions caused by catastrophes and these same adaptations also make them a source of genetic information for intrinsically stable macromolecules. This genetic information for stable macromolecules can be shared with other organisms through lateral gene transfer. Similarly, the adaptations of survivophiles increase survival during catastrophes and provide a source of genes for bio-stabilizing molecules (e.g., heat shock proteins, trehalose and other organic solutes). We conclude that the strategies and the specialized genes for growth and survival of extremophiles and survivophiles impact the continuity and perpetuity of life during global catastrophes by expanding the range of possible refugia during these events and by providing genetic information to other organisms.
Conference Committee Involvement (4)
Instruments, Methods, and Missions for Astrobiology XIII
3 August 2010 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology X
28 August 2007 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology IX
14 August 2006 | San Diego, California, United States
Instruments, Methods, and Missions for Astrobiology IX
31 July 2005 | San Diego, California, United States
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