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PubMed2025

Transcriptome-wide analysis reveals sequence selection to avoid mRNA aggregation in E. coli.

The stability of RNA base pairing and its limited four-letter code create an intrinsic potential for promiscuous RNA-RNA interactions. In vitro, such interactions drive RNA to self-assemble into aggregates. This raises a fundamental unanswered question: within a confined cellular volume at physiological mRNA abundances, how much aggregation would arise from sequence-encoded chemistry alone? Here, we establish this baseline with large-scale kinetic simulations of the E. coli transcriptome. Our simulations reveal that sequence-encoded base-pairing energetics is sufficient to generate a dynamic network of large aggregates, organized by long, multivalent mRNA hubs. Strikingly, evolutionary analysis shows that native E. coli sequences exhibit clear signatures of selection to counteract this propensity: they fold more stably, minimize unstructured regions, and form weaker intermolecular contacts than dinucleotide-preserving controls. These findings demonstrate that maintaining transcriptome solubility has been a significant, previously unrecognized constraint shaping genome evolution, and provide a new lens to interpret cellular RNA management.

Biological Sciences (Biophysics and Computational ↗
PubMed1977

Purification of protected syntheic peptides by preparative high performance liquid chromatography on silica gel 60.

A simple preparative system is described for rapid and efficient purification of protected synthetic peptides on a gram scale by high performance liquid chromatography on prepacked silica gel 60 columns. A variety of protected peptides up to tetradecapeptides have been chromatographed at pressures of 50 to 150 psi and obtained in analytically pure from within 2 to 4 h. With such commonly used protecting groups as N-benzyloxycarbonyl (Z), N-2-(p-biphenylyl)-2-propyloxycarbonyl (Bpoc), N-t-butyloxycarbonyl (Boc), O- and S-t-butyl (But), and S-acetamidomethyl (Acm), compounds were sufficiently soluble in chloroform, alcohols, acetic acid, or mixtures of these solvents for column loading. Dimethylformamide was also used as a solvent for loading. Solvent systems for column elution in isocratic, stepwise, or gradient modes were composed of chloroform, isopropanol, ethanol, or methanol and acetic acid in ratios that differed for each protected peptide depending on Rf values on t.l.c. plates. A simple chromatography is described which was self-assembled using standard instruments commonly in use in most laboratories. A shut-off valve was designed to prevent loss of material between fractions.

Chromatography, Liquid↗
PubMed1992

Cleavage of bovine brain microtubule-associated protein-2 by human immunodeficiency virus proteinase.

The high-molecular-weight dendritic cytoskeletal protein known as microtubule-associated protein (MAP)-2 displays the capacity to stimulate tubulin polymerization and to associate with microtubules. Serine proteases cleave MAP-2 into a C-terminal M(r) 28,000-35,000 microtubule-binding fragment and a larger N-terminal M(r) 240,000 projection-arm region. We now show that human immunodeficiency virus (HIV) proteinase also progressively degrades purified MAP-2 in vitro. This proteolysis reaction is characterized by transient accumulation of at least six intermediates, and most abundant of these is an M(r) 72,000 species that retains the ability to associate with taxol-stabilized microtubules. Treatment of this M(r) 72,000 species with thrombin releases the same M(r) 28,000 component as that derived from thrombin action on intact high-molecular-weight MAP-2, indicating that the viral aspartoproteinase action preferentially occurs further toward the N-terminus. The association of the M(r) 72,000 component with microtubules can be disrupted by the presence of a 21-amino acid peptide analogue of the second repeated sequence in the MAP-2 microtubule-binding region. We also studied HIV proteinase action on MAP-2 in the presence of tubulin and other MAPs that recycle with tubulin, and contrary to other published studies we found no effect of such treatment on microtubule self-assembly behavior. Cleavage of isolated MAP-2 by the HIV enzyme at high salt concentrations, followed by desalting and addition of tubulin, also resulted in microtubule assembly, albeit with slightly reduced efficiency.

Animals↗
PubMed1975

Microtubule protein pools in early development.

Microtubule protein pools have been demonstrated to exist in unfertilized eggs and the early embryonic stages of several organisms. The microtubule pool of the sea urchin embryo is constant in size (about 0.4% of the total embryo protein) throughout early development. Protein withdrawn from this pool for organelle assembly is replaced by new synthesis. Eggs and embryos of Drosophila similarly contain a pool of microtubule proteins (larger than or equal to 0.4% of the total embryo protein, congruent to 3% of the soluble protein), which is constant in size throughout early development. The Drosophila egg microtubule proteins are easily purified by self-assembly in vitro of microtubules, and are similar to microtubule proteins from other organisms in molecular weight and other properties. Synthesis of microtubule proteins in sea urchin embryos is supported by oogenetic mRNA. This appears also to be the case in molluscan (Ilyanassa) embryos. It is not known whether Drosophila embryos synthesize microtubule proteins during the early stages of development.

Animals↗
PubMed1979

Specific interaction of the tetragonally arrayed protein layer of Bacillus sphaericus with its peptidoglycan sacculus.

Tetragonal layer protein (T-layer) isolated from Bacillus sphaericus NTCC 9602 (wild type) or 9602 Lmw (variant) bonded specifically to the sacculi (peptidoglycan) of either cell type. Only uncleaved T-layer subunits were capable of specific recognition of the B. sphaericus sacculi; other Bacillus strains and gram-positive bacterial sacculi would not adsorb B. sphaericus strain 9602 T-layer. The peptidogylcan did not function as a template since isolated T-layer subunits self-assembled into characteristic pattern. Upon reassociation with sacculi, T-layer assemblies were randomly oriented patches compared with more continuous strictly oriented pattern on cells or fresh cell walls. T-layer associated with the sacculus was less susceptible to conditions that dissociated in vitro-assembled T-layer. Mild proteolysis of both wild-type and variant T-layer subunits by a variety of enzymes reduced the molecular weight by 18,000 in all cases, indicating that one region of the molecule was particularly susceptible to cleavage. Subunits from which the minor fragment had been cleaved upon aging retained the capacity to assemble in vitro, but would no longer adsorb to sacculi. Thus, the ability of T-layer to form networks was separate from its ability to bind cell walls, and the 18,000-dalton piece of the T-layer polypeptide was necessary for attachment to the cell wall.

Bacillus↗
PubMed1992

Permeability and charge-dependent adsorption properties of the S-layer lattice from Bacillus coagulans E38-66.

We investigated the permeability properties of the oblique S-layer lattice from Bacillus coagulans E38-66 after depositing cell wall fragments on a microfiltration membrane, cross-linking the S-layer protein with glutaraldehyde, and degrading the peptidoglycan with lysozyme. Comparative permeability studies on such multilayered S-layer membranes and suspended S-layer vesicles from thermophilic members of the family Bacillaceae with use of the space technique (M. Sára and U. B. Sleytr, J. Bacteriol. 169:4092-4098, 1987) revealed identical molecular exclusion limits (M. Sára and U. B. Sleytr, J. Membr. Sci. 33:27-49, 1987). Examination of the S-layer lattice from B. coagulans E38-66 with the S-layer membrane technique revealed unhindered passage for molecules up to the size of myoglobin (M(r) 17,000). The molecular dimensions of this protein (2.8 by 3.2 by 4.5 nm) correspond approximately to the size of the ovoid-shaped pore previously shown by high-resolution electron microscopy of negatively stained S-layer self-assembly products (D. Pum, M. Sára, and U. B. Sleytr, J. Bacteriol. 171:5296-5303, 1989). Chemical modification of the S-layer protein and comparative labeling, adsorption, and permeability studies clearly demonstrated that (i) in the native state, free amino and carboxyl groups are present on the outer S-layer face and in the interior of the pores and (ii) electrostatic interactions between these groups prevent unspecific adsorption of the S-layer in vivo.

Adsorption↗
PubMed1992

Recombinant vaccine for canine parvovirus in dogs.

VP2 is the major component of canine parvovirus (CPV) capsids. The VP2-coding gene was engineered to be expressed by a recombinant baculovirus under the control of the polyhedrin promoter. A transfer vector that contains the lacZ gene under the control of the p10 promoter was used in order to facilitate the selection of recombinants. The expressed VP2 was found to be structurally and immunologically indistinguishable from authentic VP2. The recombinant VP2 shows also the capability to self-assemble, forming viruslike particles similar in size and appearance to CPV virions. These viruslike particles have been used to immunize dogs in different doses and combinations of adjuvants, and the anti-CPV responses have been measured by enzyme-linked immunosorbent assay, monolayer protection assays, and an assay for the inhibition of hemagglutination. A dose of ca. 10 micrograms of VP2 was able to elicit a good protective response, higher than that obtained with a commercially available, inactivated vaccine. The results indicate that these viruslike particles can be used to protect dogs from CPV infection.

Animals↗
PubMed1992

Adaptations to high hydrostatic pressure.

The importance of adaptation to high pressure has long been implicit in the findings of studies in which 1 atm-adapted species were subjected to elevated pressures. Recent comparative studies have shown that pressure sensitivities of enzymes, structural proteins, and membrane-based systems differ markedly between shallow- and deep-living species. These studies allow operational definition of what constitutes high pressures for different biological structures and processes. These are the habitat (adaptation) pressures at which a given type of system first exhibits reduced perturbation by pressure. These threshold pressures vary among physiological systems, but are similar for a given system among different species. Dehydrogenase enzymes and adenylyl cyclases exhibit threshold perturbation pressures of only 50-100 atm; the Na(+)-K(+)-ATPase of teleost gills appears to have a pressure perturbation threshold near 200 atm, and a similar threshold was found for actin self-assembly. Even this limited sample of physiological processes indicates that the terms deep and high pressure begin to apply at depths of only 500 m or less--and processes yet to be examined in comparative analysis may yield even lower pressure thresholds. The differences in sensitivity to pressure of homologous systems in shallow- and deep-living organisms have implications at several levels of biological organization. The vertical distribution patterns of species in aquatic habitats may be established, in part, by interspecific differences in resistance to pressure. High pressures may restrict the depths to which shallow-living species can penetrate, and the obligately barophilic systems found in deep-living organisms may limit their upper distribution limits. The similarities noted among the adaptations of deep-sea species with different shallow-water ancestors reflect a high degree of convergent evolution in pressure adaptation. It will be interesting to learn if the similarities in pressure-resistance of function among diverse deep-sea species are the result of similar or identical changes at the molecular level, e.g. in protein sequence. Acclimation to pressure may be of widespread occurrence among species that undergo large changes in depth, e.g. during ontogeny. Pressure acclimation may require pressure-regulation of gene expression. Lastly, comparisons of species from the cold deep sea with those from hydrothermal vents have shown that adaptations to both temperature and pressure play critical roles in determining the distribution patterns of deep-living species.

Adaptation, Physiological↗
PubMed1977

Levels and reduction.

This paper addresses the problem of reconciling pluralism with reductionism, i.e., acknowledging both the variety of the world and the need and possibility to explain it. First the various kinds of monism and pluralism that litter the scientific and philosophical literature are examined cursorily. Then certain maligned notions are examined, mainly those of novelty, self-assembly, level, and levels "hierarchy." They are shown to be amenable to analysis and even mathematization. Then the logic of reduction is analyzed. Two kinds of reduction are distinguished: full or straight, and partial or roundabout. And three stands on reduction are examined: anti-, radical, and moderate reductionism. The former is dismissed for being obscurantist and the second for being quixotic. Moderate reductionism, aiming at the (partial) reduction of higher levels to lower ones without skipping any intermediate levels, is adopted. Finally moderate reductionism is found to be consistent with a certain variety of pluralism, characterized as naturalistic.

Logic↗
PubMed2025

IgStrand: A universal residue numbering scheme for the immunoglobulin-fold (Ig-fold) to study Ig-proteomes and Ig-interactomes.

The Immunoglobulin fold (Ig-fold) is found in proteins from all domains of life and represents the most populous fold in the human genome, with current estimates ranging from 2 to 3% of protein coding regions. That proportion is much higher in the surfaceome where Ig and Ig-like domains orchestrate cell-cell recognition, adhesion and signaling. The ability of Ig-domains to reliably fold and self-assemble through highly specific interfaces represents a remarkable property of these domains, making them key elements of molecular interaction systems: the immune system, the nervous system, the vascular system and the muscular system. We define a universal residue numbering scheme, common to all domains sharing the Ig-fold in order to study the wide spectrum of Ig-domain variants constituting the Ig-proteome and Ig-Ig interactomes at the heart of these systems. The "IgStrand numbering scheme" enables the identification of Ig structural proteomes and interactomes in and between any species, and comparative structural, functional, and evolutionary analyses. We review how Ig-domains are classified today as topological and structural variants and highlight the "Ig-fold irreducible structural signature" shared by all of them. The IgStrand numbering scheme lays the foundation for the systematic annotation of structural proteomes by detecting and accurately labeling Ig-, Ig-like and Ig-extended domains in proteins, which are poorly annotated in current databases and opens the door to accurate machine learning. Importantly, it sheds light on the robust Ig protein folding algorithm used by nature to form beta sandwich supersecondary structures. The numbering scheme powers an algorithm implemented in the interactive structural analysis software iCn3D to systematically recognize Ig-domains, annotate them and perform detailed analyses comparing any domain sharing the Ig-fold in sequence, topology and structure, regardless of their diverse topologies or origin. The scheme provides a robust fold detection and labeling mechanism that reveals unsuspected structural homologies among protein structures beyond currently identified Ig- and Ig-like domain variants. Indeed, multiple folds classified independently contain a common structural signature, in particular jelly-rolls. Examples of folds that harbor an "Ig-extended" architecture are given. Applications in protein engineering around the Ig-architecture are straightforward based on the universal numbering.

Humans↗
PubMed2026

Metal-Organic Framework-Based and Metal-Organic Framework-Derived Nanomaterials for Cancer Theranostics and Antibacterial Applications: Advances, Challenges, and Perspectives.

Metal-organic frameworks (MOFs), constructed through coordination-driven self-assembly of metal ions/clusters and organic linkers, have emerged as a uniquely versatile class of porous nanomaterials with broad biomedical potential. Despite substantial clinical progress, both oncological treatment and antimicrobial intervention remain constrained by inadequate tumor-targeting selectivity, multidrug resistance, immunosuppressive tumor microenvironments, and the global proliferation of antibiotic-resistant pathogens, limitations that conventional nanocarrier platforms have addressed only in part. MOF-based and MOF-derived nanomaterials, distinguished by tunable pore architecture, structurally and compositionally adaptable metal nodes, high surface areas, and stimulus-responsive degradability, offer a rational framework for overcoming these barriers. This review systematically examines the synthetic strategies underlying MOF-based and MOF-derived nanomaterials, including pyrolysis, chemical etching, composite modification, and functional group introduction, and their structural determinants of performance. In cancer theranostics, we critically evaluate their roles as multimodal imaging contrast agents, stimulus-responsive drug delivery carriers, and platforms for combination therapies encompassing photodynamic, photothermal, chemodynamic, and immunomodulatory modalities. In antibacterial applications, we analyze the mechanistic basis of MOF-based and MOF-derived activity, including physical membrane disruption, reactive oxygen species-mediated oxidative stress, and sustained metal ion release, alongside strategies targeting biofilm formation and antibiotic resistance. Multifunctional platforms that concurrently integrate cancer theranostic and antibacterial capabilities are further discussed. This review also addresses the principal barriers to clinical translation, encompassing large-scale manufacturing, long-term biosafety, and regulatory approval, and proposes future directions incorporating artificial intelligence-assisted design and materials genomics, underscoring the transformative potential of MOF-based and MOF-derived nanomaterials as next-generation precision nanomedicines. This review establishes a unified mechanistic framework grounded in the intrinsic physicochemical properties of MOF-derived nanomaterials, systematically integrating their applications in cancer theranostics and antibacterial therapy. Critically, it bridges fundamental advances with translational reality by incorporating a rigorous assessment of regulatory pathways, scalable manufacturing constraints, and clinical implementation barriers, and offers a comprehensive, practice-oriented reference for the rational design and responsible translation of MOF-based and MOF-derived nanomaterials.

Theranostic Nanomedicine↗
PubMed1976

Review: Casein micelle structure; an examination of models.

The casein micelle system of bovine milk is unique in that protein aggregates of similar spherical shape but extreme variability of size are formed by the self-assembly of three major nonidentical subunits. The monomeric subunits appear to be approximately the same size and shape with similar amphiphilic natures, the chief difference in properties being in the carbohydrate-containing kappa-casein which acts to stabilize the system against precipitation by calcium ion. Micelle models with kappa-casein exclusively in the interior lack a stabilization mechanism and can be eliminated. Statistical considerations of a chain polymer model also lead to its rejection. Electron microscopy reveals spherical submicellar aggregates which at present can be accounted for by only three models. Of these three, the experimental data are predicted only by one in which, alphas 1-, beta-, and kappa-casein subunits are associated into spherical soap micelle-like particles with the kappa-casein segregated into one portion, giving these submicelles an amphiphilic nature. The alphas 1- and beta-caseins are hydrophobic while the kappa-casein portion of the submicelle surface is hydrophilic. Of particular interest is the ability of this micelle model to explain the formation of a minimum micelle which is larger than a submicellar particle.

Amino Acid Sequence↗
PubMed1975

The matrix of the optic vesicle-presumptive lens interface during induction of the lens in the chicken embryo.

The cell coats of the presumptive lens cells and the extracellular interface between the lens rudiment and optic vesicle were investigated in the chicken embryo throughout the period during which lens induction is presumed to take place. Histochemical methods showed that the cell coats contained both glycoproteins and glycosaminoglycans. Autoradiography after [3H]glucosamine injection indicated incorporation of the precursor with subsequent localization primarily at the cell surface. No obvious changes in the properties of the coat were noted with the progression of early lens morphogenesis. The extracellular matrix at the interface between ectoderm and optic vesicle also contained glycoprotein and glycosaminoglycan. There was a heavy concentration of [3H]glucosamine-containing macromolecules in the area. Electron microscopy revealed that the interface consisted of the basement membrane systems of lens and optic vesicle, fused with their external fibrillar layers. In contrast to the findings on cell coats the density of the interfacial matrix increases appreciably during the lens induction period. Evidence suggests that the cells of the two ocular epithelia are themselves the source of the matrix materials. It is proposed that the macromolecules excreted by the epithelial cells into the interface interact at different concentrations to form aggregates of various structure by a process of self-assembly. This may be reflected in the different ultrastructure of the layers of the interfacial matrix. Quantitative changes in the density of the matrix, leading to increased adhesion between lens rudiment and optic vesicle, may restrict the lateral spreading of the lens cells and so fix the basal area of the lens rudiment. This, together with continued cell replication, may produce the cell crowding, placode formation and invagination characteristic of lens morphogenesis.

Amylases↗
PubMed1975

[Interaction of the components of the cytochrome P-450 monooxygenase system from liver microsomes. I. Immobilization of the solubilized and partially purified protein components].

The method of matrix fixation has been used to study the interaction between the components of the cytochrome P-450 monooxygenases from rat liver microsomes. The solubilized, isolated protein components were covalently bound to BrCN-activated. Sepharose in different ways and subsequently the N-demethylase activity was determined. It has been proved that in each case of fixation a certain amount of activity could be determined. However the degree of activity varied in dependence on the sequence and number of bound components. The activity compared with the reconstituted soluble system decreased in the following sequence: single fixation of NADPH-cytochrome P-450 reductase (40%), of cytochrome P-450 (23%); sequential fixation: first component cytochrome P-450 (33%), first component NADPH-cytochrome P-450 reductase (8%). Simultaneous fixation of both components yielded a lower activity. From the results it was concluded that the activity is influenced by some kind of self-assembly.

Animals↗
PubMed1992

Polymerization of pNcollagen I and copolymerization of pNcollagen I with collagen I. A kinetic, thermodynamic, and morphologic study.

Previous observations established that pNcollagen III copolymerized with collagen I and decreased the diameter of the fibrils formed (Romanic, A.M., Adachi, E., Kadler, K.E., Hojima, Y., and Prockop, D.J. (1991) J. Biol. Chem. 266, 12703-12709). Here, procollagen I alone or mixtures of procollagen I and pCcollagen I were incubated with procollagen C-proteinase to generate pNcollagen I or mixtures of pNcollagen I and collagen I. The results confirmed previous reports that pNcollagen I assembles into sheet-like structures. They also demonstrated that polymerization of pNcollagen I exhibits a lag period and propagation phase similar to those seen with other protein self-assembly systems. In addition, the results demonstrated that pNcollagen I formed true copolymers with collagen I in that the presence of pNcollagen I increased the lag time, decreased the propagation rate, and increased the concentration of collagen I in solution at equilibrium. Copolymerization of pNcollagen I with collagen I, however, differed in two features from copolymerization of pNcollagen III with collagen I. One was that, in confirmation of previous work, copolymerization of pNcollagen I with collagen I markedly altered the circularity of the fibrils formed. The second difference was that the copolymerization increased the concentration in solution at equilibrium of pNcollagen I whereas copolymerization with collagen I was previously shown to decrease the concentration in solution of pNcollagen III. The increase in concentration in solution of pNcollagen I was explicable either by the assembly of soluble oligomers of pNcollagen I and collagen I, or by subtle changes in the activities of pNcollagen I and collagen I in the solid-phase. Comparison with previous data with pNcollagen III indicated that although pNcollagen I and pNcollagen III copolymerize with collagen I, there are marked differences in the two kinds of copolymers.

Collagen↗
PubMed1992

Epitope mapping of anti-recA protein IgGs by region specified polymerase chain reaction mutagenesis.

Monoclonal IgGs were shown to be useful for the specific inhibition of a set of activities of the recA protein, a key protein in homologous genetic recombination. The mapping of the epitopes for these IgGs and site-directed mutagenesis based on the mapping will facilitate location of the functionally active sites on the tertiary structure of the protein, which is being solved by means of physicochemical techniques. We developed a novel technique for region-specified mutagenesis and applied the technique to epitope mapping. Using the polymerase chain reaction in the presence of deoxyinosine triphosphate, we introduced random base substitutions specifically into a region of the recA gene defined by a pair of primers. RecA mutants exhibiting altered antigenicity were selected, in plaque-immunoblotting experiments, from libraries of mutagenized recA genes constructed on the lambda gt11 expression vector. Mutant recA genes were obtained at the frequency of about 10(-2) among the plaques expressing fused recA genes and then each one was expressed as a whole protein, which was characterized by enzyme-linked immunosorbent assay. Analyzing the DNA sequences of the mutant recA genes, we located at the amino acid sequence level the epitopes for two anti-recA IgGs which could not be located in previous studies. One of the antibodies was shown to prevent self-assembly of the recA protein and the other was suggested to inhibit the binding of double-stranded DNA. Thus, the active sites involved in these functions would be located in the space around or near the relevant epitope.

Amino Acid Sequence↗
PubMedDate not supplied

[Role of phospholipids in the generation of membrane potentials by proteoliposomes].

Closed protein-phospholipid particles (proteoliposomes), obtained by self-assembly method, are capable to generate and to maintain the membrane potential in the case if their protein complex is represented by: a) a complex of mitochondrial ATPase; b) a complex of cytochrome oxidase and cytochrome c and c) bacteriorhodopsin from Halobacterium halobium; and their phospholipid component is represented by phosphatidylethanolamine or by a mixture of mitochondrial phospholipids. Only cytochromoxidase and bacteriorhodopsin (but not ATPase) proteoliposomes with phosphatidylserine are active. Cardiolipin also is not active in experiments with ATPase. Phosphatidylcholine produces in all the cases proteoliposomes incapable of maintaining the membrane potential. It is concluded that the inefficiency of phosphatidylcholine in the formation of proteoliposomes, generating the membrane potential, is due to the impossibility of obtaining closed membrane forms with a high electric resistance. The inefficiency of phosphatidylserine and cardiolipine, in the case of ATPase protein component of proteoliposomes, may be due to a specific requirement of this generator of the membrane potential in phosphatidylethanolamine.

Adenosine Triphosphatases↗
PubMed1978

Protein-lipid interactions and the role of water.

The rigidity of the three-dimensional structure of a native protein is dependent on the network of hydrogen-bonded groups which provide the scaffolding for the other interactions. The structure is stabilized by the hydrophobic interactions of the nonpolar side chains. The latter are formed by the very unfavorable entropy change that occurs in water but not in less-polar solvents. It is unlikely that any solvent other than water can produce the same folding of a polypeptide chain to form the active native structure. Water plays a unique role, since it alone is responsible for the heat capacity changes observed when nonpolar groups are transferred from an aqueous to a nonaqueous environment, as exists in the interior of a protein. The need to juxtapose like groups and to avoid making contact among unlike groups imposes severe restrictions on the binding of small or large molecules to proteins. Consequently there must be proper pairing of polarities as well as close fitting of ligands for strong binding to occur. This is clearly evident from the x-ray studies of proteins containing subunits or prosthetic groups. The thermodynamic parameters observed in the most complex protein reactions--i.e., self-assembly systems--resemble rather well those observed in micelle association reactions or even in the solution of nonpolar gases in water. This interaction--hydrophobic--can be looked upon as the controlling reaction which stabilized the organized structures of most cellular entities aside from nucleic acids--i.e., membranes and organelles.

Butanes↗