Concept Of Self-assembly Research Articles

Self-assembling protein arrays on DNA chips by auto-labeling fusion proteins with a single DNA address

The high-throughput deposition of recombinant proteins on chips, beads or biosensor devices would be greatly facilitated by the implementation of self-assembly concepts. DNA-directed immobilization via conjugation of proteins to an oligonucleotide would be preeminently suited for this purpose. Here, we present a unique method to attach a single DNA address to proteins in one step during the purification from the E. coli lysate by fusion to human O6-alkylguanine-DNA-alkyltransferase (SNAP-tag) and the Avitag. Use of the conjugates in converting a DNA chip into a protein chip by self assembly is demonstrated.

Synthesis and Retrostructural Analysis of Libraries of AB3 and Constitutional Isomeric AB2 Phenylpropyl Ether-Based Supramolecular Dendrimers

We report the synthesis of methyl esters of 3-(4-hydroxyphenyl)propionic, 3-(3,4-dihydroxyphenyl)propionic, 3-(3,5-dihydroxyphenyl)propionic, and 3-(3,4,5-trihydroxyphenyl)propionic acids and their use in a convergent iterative strategy to prepare up to four generations of three libraries, one of 3,4,5- and two of constitutional isomeric 3,4- and 3,5-substituted 3-phenylpropyl dendrons. Each library contains 3-[3,4,5-tris(dodecyl-1-oxy)phenyl]propyl-, 3-[3,4-bis(dodecyl-1-oxy)phenyl]propyl-, 3-{3,4-bis[3-(4-dodecyl-1-oxyphenyl)propyl-1-oxy]phenyl}propyl-, and 3-{3,4,5-tris[3-(4-dodecyl-1-oxyphenyl)propyl-1-oxy]phenyl}propyl ether first-generation dendrons on their periphery and -CO2CH3, -COOH, and -CH2OH groups at their apex. Regardless of their generation number and their periphery, internal, and apex structures, these dendrons self-assemble into supramolecular dendrimers that self-organize into all periodic and quasi-periodic assemblies encountered previously and in several unencountered with architecturally related benzyl ether-based supramolecular dendrimers. A variety of porous columnar lattices that were previously obtained only from dendritic dipeptides and hollow supramolecular spheres were also discovered from these building blocks. The more flexible and less compact 3-phenylpropyl ether repeat units are stable under acidic conditions, facilitate a simpler synthetic strategy, provide faster dynamics of self-assembly into higher-order supramolecular structures of larger dimensions, exhibit lower transition temperatures than the corresponding benzyl ether homologues, and demonstrate the generality of the self-assembly concept based on amphiphilic dendrons.

Methods for scalable self-assembly of ad hoc wireless sensor networks

In distributed wireless sensing applications such as unattended ground sensor systems, remote planetary exploration, and condition-based maintenance, where the deployment site is remote and/or the scale of the network is large, individual emplacement and configuration of the sensor nodes is difficult. Hence, network self-assembly and continuous network self-organization during the lifetime of the network in a reliable, efficient, and scalable manner are crucial for successful deployment and operation of such networks. This paper provides an overview of the concept of network self-assembly for ad hoc wireless sensor networks at the link layer, with descriptions of results from implementation of a novel network formation mechanism for wireless unattended ground sensor applications using a multicluster hierarchical topology and a novel dual-radio architecture.

Self-assembly using dynamic combinatorial chemistry.

The principles of an evolution-selection approach to the synthesis of systems capable of molecular recognition are described. Using this dynamic combinatorial self-assembly concept in bulk solution, a variety of successful synthetic receptors have been prepared. The reversible chemistries employed include metalloporphyrin-ligand coordination, hydrazone exchange and disulfide exchange. The prospects for extension of the approach to surfaces are briefly considered.

Mesoscale organization of CuO nanoribbons: formation of "dandelions".

A two-tiered organizing scheme with multiple-length scales for construction of dandelion-like hollow CuO microspheres has been elucidated: (1) mesoscale formation of rhombic building units from smaller nanoribbons via oriented aggregation and (2) macroscopic organization of these units into the CuO microspheres. This self-assembly concept may also be applicable to other metal oxides by creating geometric constraints for constructional units.

Mastering molecular matter. Supramolecular architectures by hierarchical self-assembly

Since the serendipitous event that led to the first synthesis of a molecule by the hands of Man in 1826, the creation of molecular matter depended for 150 years on linking together molecules from other molecular building blocks with the help of strong covalent bonds. The advent of supramolecular chemistry in the last decades of the 20th century has provided chemists with a wealth of new possibilities to synthesize molecular structures and materials that are held together by relatively weak, non-covalent interactions, such as hydrogen bonding, π–π stacking, electrostatic and van der Waals interactions. Using nature as a source of inspiration, the creation of even more complex supramolecular architectures has recently become possible by applying the concept of hierarchical self-assembly, i.e. the non-covalent organization of molecules and macromolecules which takes places over distinct multiple levels, in which the assembly processes gradually decrease in strength. This review will focus on some recent discoveries in the field of spontaneous hierarchical organization of synthetic amphiphiles, disk-like molecules and concave building blocks into well-defined nano-sized assemblies.

Introduction to supramolecular chemistry

The definition, scope and related informations about supramolecular chemistry have been reviewed. Emphasis has been given to the concepts of molecular recognition, molecular self-assembly, molecular devices, supramolecular materials and supramolecular catalysis.

Self-assembly at all scales.

Self-assembly is the autonomous organization of components into patterns or structures without human intervention. Self-assembling processes are common throughout nature and technology. They involve components from the molecular (crystals) to the planetary (weather systems) scale and many different kinds of interactions. The concept of self-assembly is used increasingly in many disciplines, with a different flavor and emphasis in each.

Molecular organization of histidine-tagged biomolecules at self-assembled lipid interfaces using a novel class of chelator lipids.

In molecular biology, the expression of fusion proteins is a very useful and well-established technique for the identification and one-step purification of gene products. Even a short fused sequence of five or six histidines enables proteins to bind to an immobilized metal ion chelate complex. By synthesis of a class of chelator lipids, we have transferred this approach to the concept of self-assembly. The specific interaction and lateral organization of a fluorescent fusion molecule containing a C-terminal oligohistidine sequence was studied by film balance techniques in combination with epifluorescence microscopy. Due to the phase behavior of the various lipid mixtures used, the chelator lipids can be laterally structured, generating two-dimensional arrays of histidine-tagged biomolecules. Because of the large variety of fusion proteins already available, this concept represents a powerful technique for orientation and organization of proteins at lipid interfaces with applications in biosensing, biofunctionalization of nanostructured interfaces, two-dimensional crystallization, and studies of lipid-anchored proteins.

Studies directed toward the fabrication of a synthetic cation-conducting channel based on lariat ethers: The feeble forces concept for self-assembly

The work described here derives from our observation that while Nature certainly utilizes covalent interactions and other forces of great strength in the construction of biomolecules, many ‘feeble forces’ are involved as well. We have used feeble forces in model studies directed eventually to the synthesis of a self-assembling, cation-conducting channel. Specifically, we have prepared three models for portions of such a cation-conducting channel. The first is based on the steroidal lariat ethers that clearly self-assemble. This process involves inter alia entropy as a feeble force of cumulative importance. Second, we have prepared three tris(macrocyclic) systems that are simplified versions of the proposed channel-former. Third, we have demonstrated the strength of carefully-conceived hydrogen bonding interactions by constructing a molecular box based on the interaction between adenine and thymine.

In vitro assembly of 30S ribosomal particles from precursor 16S RNA of Escherichia coli.

THE concept of self-assembly has been shown to apply to the assembly of the Escherichia coli 30S ribosome in vitro by Nomura and his co-workers1,2. The reconstitution of functional 30S ribosomes from purified mature 16S RNA (m16 RNA in the nomenclature of Hecht and Woese3) and total 30S proteins has been studied in detail. The macromolecular information necessary for this in vitro assembly clearly resides in the component parts with no requirements for enzymes or cellular structures (such as membranes) which are not ultimately part of the 30S ribosome. The reconstitution system developed by Traub and Nomura1 has been useful in a variety of studies which have greatly aided our understanding of ribosome assembly, structure, and function. The biosynthesis of ribosomes, however, is known to differ in several ways from this in vitro reconstitution. The in vivo process is composed of a series of cooperative and sequential interactions between the primary ribosomal UNA transcripts and of ribosomal proteins, as well as the modification of both RNA and protein4,5.

Spontaneous generation, the origin of life, and self assembly

A discussion dealing with the history of the concept of self assembly in its relation to the origin of life. Self assembly not only embraces the nineteenth century concept of ‘spontenous generation’, but applies conceptually to the origins of precellular polymers and systmes as well as to contemporary biopolymers and cellular structures.