Designed Protein- and Peptide-based Hydrogels for Biomedical Sciences

Author(s):  
Wonkyung Ahn ◽  
Jong-Hwan Lee ◽  
SOO RIN KIM ◽  
Jeewon Lee ◽  
Eun Jung Lee

Proteins are fundamentally the most important macromolecules for biochemical, mechanical, and structural functions in living organisms. Therefore, they provide us with diverse structural building blocks for constructing various types of...

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ling Xin ◽  
Xiaoyang Duan ◽  
Na Liu

AbstractIn living organisms, proteins are organized prevalently through a self-association mechanism to form dimers and oligomers, which often confer new functions at the intermolecular interfaces. Despite the progress on DNA-assembled artificial systems, endeavors have been largely paid to achieve monomeric nanostructures that mimic motor proteins for a single type of motion. Here, we demonstrate a DNA-assembled building block with rotary and walking modules, which can introduce new motion through dimerization and oligomerization. The building block is a chiral system, comprising two interacting gold nanorods to perform rotation and walking, respectively. Through dimerization, two building blocks can form a dimer to yield coordinated sliding. Further oligomerization leads to higher-order structures, containing alternating rotation and sliding dimer interfaces to impose structural twisting. Our hierarchical assembly scheme offers a design blueprint to construct DNA-assembled advanced architectures with high degrees of freedom to tailor the optical responses and regulate multi-motion on the nanoscale.


2015 ◽  
Vol 112 (27) ◽  
pp. 8187-8192 ◽  
Author(s):  
Michael D. Hardy ◽  
Jun Yang ◽  
Jangir Selimkhanov ◽  
Christian M. Cole ◽  
Lev S. Tsimring ◽  
...  

Cell membranes are dynamic structures found in all living organisms. There have been numerous constructs that model phospholipid membranes. However, unlike natural membranes, these biomimetic systems cannot sustain growth owing to an inability to replenish phospholipid-synthesizing catalysts. Here we report on the design and synthesis of artificial membranes embedded with synthetic, self-reproducing catalysts capable of perpetuating phospholipid bilayer formation. Replacing the complex biochemical pathways used in nature with an autocatalyst that also drives lipid synthesis leads to the continual formation of triazole phospholipids and membrane-bound oligotriazole catalysts from simpler starting materials. In addition to continual phospholipid synthesis and vesicle growth, the synthetic membranes are capable of remodeling their physical composition in response to changes in the environment by preferentially incorporating specific precursors. These results demonstrate that complex membranes capable of indefinite self-synthesis can emerge when supplied with simpler chemical building blocks.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Aleksey E. Kuznetsov

Abstract Various (metallo)porphyrins and related compounds have been intensively investigated by different research groups due to their extremely important role in living organisms along with their versatile applications in technology. The design of novel porphyrinoids by core-modification, or substitution of pyrrole nitrogens, with the elements of other groups of the Periodic Table has been considered as a highly promising methodology for tuning structures and properties of porphyrinoids and thus opening new possible applications for them. Much effort has been given to the modifications of the porphyrin core with elements of the main groups, namely O, S, Se (chalcogens), and the heavier congener of nitrogen, phosphorus. In general, the porphyrin core modification by replacing nitrogens with heteroatoms is a promising and effective strategy for obtaining new compounds with unusual structures and properties (optical, electrochemical, coordinating, etc.) as well as reactivity. These novel molecules can also be employed as promising building or construction blocks in various applications in the nanotechnology area.


2007 ◽  
Vol 6 (4) ◽  
pp. 267-271 ◽  
Author(s):  
Avnish Kumar Arora ◽  
Varsha Tomar ◽  
Aarti ◽  
K.T. Venkateswararao ◽  
Kamaluddin

AbstractRecent findings on the presence of water on Mars (Baker, V.R. (2006). Geomorphological evidence for water on Mars. Elements2(3), 139–143; DeJong, E. (2006). Geological evidence of the presence of water on Mars. Abstracts from the 40th Western Regional Meeting of the American Chemical Society, Anaheim, CA, January, 2006, pp. 22–25. American Chemical Society, Washington, DC; McSween, H.Y. Jr. (2006). Water on Mars. Elements2(3), 135–137; Mitrofanov, I.G. (2005). Water explorations on Mars. Priroda9, 34–43) strongly suggest that there existed a period of chemical evolution eventually leading to life processes on primitive Mars (Kanavarioti, A. & Maneinelli, R.L. (1990). Could organic matter have been preserved on Mars for 3.5 billion years. Icarus84, 196–202). Owing to the adverse conditions, it is quite likely that the process of chemical evolution would have been suppressed and any living organisms that formed would have become extinct over time on Mars. The presence of water as a necessity for the survival of living organisms and the presence of grey haematite, originated under aqueous conditions, have led us to investigate the possible role of haematite in the chemical evolution on Mars. Our observations suggest that iron oxide hydroxide (FeOOH), a precursor of haematite, has a much higher binding affinity towards ribose nucleotides (the building blocks of RNA) than the haematite itself. This would mean that during the process of haematite formation, especially through the probable process of Fe3+ hydrolysis by aqueous ammonia, the precursors of haematite might have played a significant role in the processes leading to chemical evolution and the possible origin of life on Mars.


2000 ◽  
Vol 23 (5) ◽  
pp. 727-741 ◽  
Author(s):  
Peter M. Todd ◽  
Gerd Gigerenzer

How can anyone be rational in a world where knowledge is limited, time is pressing, and deep thought is often an unattainable luxury? Traditional models of unbounded rationality and optimization in cognitive science, economics, and animal behavior have tended to view decision-makers as possessing supernatural powers of reason, limitless knowledge, and endless time. But understanding decisions in the real world requires a more psychologically plausible notion of bounded rationality. In Simple heuristics that make us smart (Gigerenzer et al. 1999), we explore fast and frugal heuristics – simple rules in the mind's adaptive toolbox for making decisions with realistic mental resources. These heuristics can enable both living organisms and artificial systems to make smart choices quickly and with a minimum of information by exploiting the way that information is structured in particular environments. In this précis, we show how simple building blocks that control information search, stop search, and make decisions can be put together to form classes of heuristics, including: ignorance-based and one-reason decision making for choice, elimination models for categorization, and satisficing heuristics for sequential search. These simple heuristics perform comparably to more complex algorithms, particularly when generalizing to new data – that is, simplicity leads to robustness. We present evidence regarding when people use simple heuristics and describe the challenges to be addressed by this research program.


2011 ◽  
Vol 58 (2) ◽  
Author(s):  
Hieronim Jakubowski

All living organisms conduct protein synthesis with a high degree of accuracy maintained in the transmission and flow of information from a gene to protein product. One crucial 'quality control' point in maintaining a high level of accuracy is the selectivity by which aminoacyl-tRNA synthetases furnish correctly activated amino acids, attached to tRNA species, as the building blocks for growing protein chains. When differences in binding energies of amino acids to an aminoacyl-tRNA synthetase are inadequate, editing is used as a major determinant of enzyme selectivity. Some incorrect amino acids are edited at the active site before the transfer to tRNA (pre-transfer editing), while others are edited after transfer to tRNA at a separate editing site (post-transfer editing). Access of natural non-protein amino acids, such as homocysteine, homoserine, or ornithine to the genetic code is prevented by the editing function of aminoacyl-tRNA synthetases. Disabling editing function leads to tRNA mischarging errors and incorporation of incorrect amino acids into protein, which is detrimental to cell homeostasis and inhibits growth. Continuous homocysteine editing by methionyl-tRNA synthetase, resulting in the synthesis of homocysteine thiolactone, is part of the process of tRNA aminoacylation in living organisms, from bacteria to man. Excessive homocysteine thiolactone synthesis in hyperhomocysteinemia caused by genetic or nutritional deficiencies is linked to human vascular and neurological diseases.


Chemical compounds of biogenic elements are considered (i.e., chemical elements present in living organisms and ensuring the successful functioning of their various organs and systems). Biogenic elements are divided into s-, p-, and d-elements, in which respectively are completed with s-, p-, and d-electronic orbitals. In each of these groups, the structure of compounds of biogenic elements is investigated, and the dimension of the corresponding molecules is determined. It is proved that s- and d-biogenic elements exhibit increased chemical activity (higher than the standard valence) due to participation in the formation of a chemical bond of electrons of the preceding level. This leads to the creation of complex molecules of higher dimension. The chemical compounds of biogenic p-elements, which are the building blocks for the formation of biomolecules (elements of life), will be specifically investigated in subsequent chapters.


2021 ◽  
Vol 22 (13) ◽  
pp. 6913
Author(s):  
Lara Coppi ◽  
Simona Ligorio ◽  
Nico Mitro ◽  
Donatella Caruso ◽  
Emma De Fabiani ◽  
...  

Metabolism is the central engine of living organisms as it provides energy and building blocks for many essential components of each cell, which are required for specific functions in different tissues. Mitochondria are the main site for energy production in living organisms and they also provide intermediate metabolites required for the synthesis of other biologically relevant molecules. Such cellular processes are finely tuned at different levels, including allosteric regulation, posttranslational modifications, and transcription of genes encoding key proteins in metabolic pathways. Peroxisome proliferator activated receptor γ coactivator 1 (PGC1) proteins are transcriptional coactivators involved in the regulation of many cellular processes, mostly ascribable to metabolic pathways. Here, we will discuss some aspects of the cellular processes regulated by PGC1s, bringing up some examples of their role in mitochondrial and cellular metabolism, and how metabolic regulation in mitochondria by members of the PGC1 family affects the immune system. We will analyze how PGC1 proteins are regulated at the transcriptional and posttranslational level and will also examine other regulators of mitochondrial metabolism and the related cellular functions, considering approaches to identify novel mitochondrial regulators and their role in physiology and disease. Finally, we will analyze possible therapeutical perspectives currently under assessment that are applicable to different disease states.


Author(s):  
Ahyoung Kim ◽  
Lehan Yao ◽  
Falon Kalutantirige ◽  
Shan Zhou ◽  
Qian Chen

Biological building blocks (i.e., proteins) are encoded with the information of target structure into the chemical and morphological patches, guiding their assembly into the levels of functional structures that are crucial for living organisms. Learning from nature, researchers have been attracted to the artificial analogues, “patchy particles,” which have controlled geometries of patches that serve as directional bonding sites. However, unlike the abundant studies of micron-scale patchy particles, which demonstrated complex assembly structures and unique behaviors attributed to the patches, research on patchy nanoparticles (NPs) has remained challenging. In the present chapter, we discuss the recent understandings on patchy NP design and synthesis strategies, and physical principles of their assembly behaviors, which are the main factors to program patchy NP self-assembly into target structures that cannot be achieved by conventional non-patched NPs. We further summarize the self-assembly of patchy NPs under external fields, in simulation, and in kinetically controlled assembly pathways, to show the structural richness patchy NPs bring. The patchy NP assembly is novel by their structures as well as the multicomponent features, and thus exhibits unique optical, chemical, and mechanical properties, potentially aiding applications in catalysts, photonic crystals, and metamaterials as well as fundamental nanoscience.


MRS Bulletin ◽  
1999 ◽  
Vol 24 (10) ◽  
pp. 22-26 ◽  
Author(s):  
Olivier Thoumine ◽  
Albrecht Ott

Cells are a complex topic of study for materials scientists. They are the fundamental building blocks of living organisms, able to sense their environment and act in response to it. In addition to their many biochemical functions, cells also play a mechanical role: They hold organs in place and move to the locations where they are needed in processes like wound healing, metastasis, or embryogenesis. Their mechanical behavior is mostly determined by a meshwork of three types of connected biopolymers (actin microfilaments, microtubules, and intermediate filaments) that compose a structural framework called the cytoskeleton, surrounded by a lipid membrane (Figure 1). In contrast to this simple picture, cells are very different from polymer gels or liposomes: They are active materials, powered by chemically stored energy. Their mechanical condition is closely linked to their biochemical function; for example, they may “commit suicide,” following a well-defined protocol known as apoptosis, which can be triggered by their mechanical state.The enormous progress of modern cell biology combined with new micromanipulation techniques is leading researchers toward a more global understanding of the mechanical properties of cells and toward finding a functional link between biochemistry, chemical signaling, and cell mechanics, thus crossing the boundaries between these subjects.The characterization of cell mechanical behavior has been the object of numerous studies. Red blood cells are a simple model system; if deprived of a nucleus while retaining a constant surface area, they have properties reminiscent of lipid vesicles.


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