Helix → β conformational transition of poly(<scp>L</scp>‐lysine) on dye binding

Scaria, Puthupparampil V.; Atreyi, M.; Rao, M. V. R.

doi:10.1002/bip.360251212

Cited by 16 publications

(1 citation statement)

References 23 publications

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“…In aqueous solution, free nucleic acid bases and certain dye molecules manifest a pronounced tendency for stacking (34,35). It is well documented (36)(37)(38)(39)(40) that the binding of these ligands by polylysine or polyarginine is characterized by positive cooperativity, i.e., the incoming ligands show a marked preference for binding to sites adjacent to those already occupied. This preference has been attributed to the effect of charge neutralization, upon addition of a positively charged polymer, on the tendency for negatively charged ligands to stack.…”

Section: Discussionmentioning

confidence: 99%

The binding of bilirubin by immobilized oligopeptides containing lysine

Bouvier¹,

Brown²,

St-Pierre³

1989

Can. J. Chem.

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. Can. J. Chem. 67, 596 (1989).Peptides consisting of portions of the sequence Arg-(Ly~)~-(Ser)~-Lys-(Ala)~ have been immobilized onto a polyacrylamide support by solid phase peptide synthesis. Isotherms at 0°C for the adsorption of bilirubin from phosphate buffer by these peptide resins are highly dependent on pH, in the range 7.80-11.00, demonstrating the importance of ionic interactions. The adsorption behaviour of bilirubin-related tetrapyrroles shows that structural factors also influence the process. Peptide resins containing two or more residues of lysine have two binding sites on each pendant and are characterized by positive cooperativity , to a degree that is highly dependent on the number of residues. It is proposed that bilirubin molecules bound by lysine-containing pendants are stacked, the dimer state being stabilized by T-w electron interactions, hydrogen bonds, and hydrophobic interactions. Site binding constants show that arginine-containing pendants manifest a stronger affinity for bilirubin.Key words: bilirubin, adsorption, lysine, oligopeptides, cooperativity. Chem. 67,596 (1989).Des peptides consistant en diffkrentes portions de la sCquence Arg-(Ly~)~-(Ser)~-Lys-(Ala)~ ont Ct C greffCs, via la technique de synthkse en phase solide des peptides, i un support de polyacrylamide rCticulC. Des isothermes caracterisant I'adsorption de la bilirubine en milieu tampon, B O°C, par ces adsorbants sont dCpendants du pH, dans l'inte~alle 7,80-11,00, dCmontrant ainsi l'importance des interactions ioniques. L'adsorption de tCtrapyrroles similaires B la molCcule de bilirubine a dCmontrC que des facteurs reliCs i la structure du ligand influencent 1e processus d'association. Les adsorbants qui contiennent deux rksidus de lysine ou plus ont deux sites d'adsorption par pendant et sont caractCrisCs par un mode d'adsorption B coopCrativitC positive, le degrC duquel est dependant du nombre de residus de lysine dans la sCquence. I1 est propose que les pendants contenant des rksidus de lysine favorisent la dimtrisation des molCcules de bilirubine liCes, le dimere Ctant stabilisC par des interactions w-a, des ponts hydrogenes et des interactions hydrophobiques. Des constantes d'association ont dCmontrCes que les pendants qui contiennent des rCsidus d'arginine manifestent une grande affinitC pour la bilirubine.

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Section: Discussionmentioning

confidence: 99%

The binding of bilirubin by immobilized oligopeptides containing lysine

Bouvier¹,

Brown²,

St-Pierre³

1989

Can. J. Chem.

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Sulfobetaine polyurethane ionomers, 4. Study of interactions between polymers and methyl orange

Buruiană¹,

Airinei²,

Buruiana³

et al. 1994

Angew. Makromol. Chem.

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The photochemical behaviour of some polyurethane zwitterionomers containing azoaromatic structures of dye type was studied both in solution and polymer film. The interaction between methyl orange and the sulfobetaine structures of the polyurethane chain was followed by electronic absorption spectra. ZUSAMMENFASSUNG:Das photochemische Verhalten einiger Sulfobetain-Zwitterionomerer mit azoaromatischen Farbstoffstrukturen wurde sowohl in Liisung als auch an Polymerfilmen untersucht. Die Wechselwirkung zwischen Methylorange und den Sulfobetain-Einheiten in der Polyurethankette wurde mittels UV-VIS-Spektroskopie untersucht. a Part 3 cf.6. 0 1994 Huthig & Wepf Verlag, Base1 CCC 0003-3 146/94/$05.00

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Monte carlo studies on equilibrium globular protein folding. I. Homopolymeric lattice models of β‐barrel proteins

1987

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SynopsisDynamic Monte Carlo studies have been performed on various diamond lattice models of 8-proteins. Unlike previous work, no bias toward the native state is introduced; instead, the protein is allowed to freely hunt through all of phase space to find the equilibrium conformation.Thus, these systems may aid in the elucidation of the rules governing protein folding from a given primary sequence; in particular, the interplay of short-vs long-range interaction can be explored.Three distinct models (A-C) were examined. In model A, in addition to the preference for trans (t) over gauche states ( g ' and g -) (thereby perhaps favoring 8-sheet formation), attractive interactions are allowed between all nonbonded, nearest neighbor pairs of segments. If the molecules posses a relatively large fraction of t states in the denatured form, on cooling spontaneous collapse to a well-defined 8-barrel is observed. Unfortunately, in model A the denatured state exhibits too much secondary structure to correctly model the globular protein collapse transition. Thus in models B and C, the local stiffness is reduced. In model B, in the absence of long-range interactions, t and g states are equally weighted, and cooperativity is introduced by favoring formation of adjacent pairs of nonbonded (but not necessarily parallel) t states. While the denatured state of these systems behaves like a random coil, their native globular structure is poorly defined. Model C retains the cooperativity of model B but allows for a slight preference of t over g states in the short-range interactions. Here, the denatured state is indistinguishable from a random coil, and the globular state is a well-defined /%barrel. Over a range of chain lengths, the collapse is well represented by an all-or-none model. Hence, model C possess the essential qualitative features observed in real globular proteins. These studies strongly suggest that the uniqueness of the globular conformation requires some residual secondary structure to be present in the denatured state.

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Helix → β conformational transition of poly(L‐lysine) on dye binding

Cited by 16 publications

References 23 publications

The binding of bilirubin by immobilized oligopeptides containing lysine

The binding of bilirubin by immobilized oligopeptides containing lysine

Sulfobetaine polyurethane ionomers, 4. Study of interactions between polymers and methyl orange

Monte carlo studies on equilibrium globular protein folding. I. Homopolymeric lattice models of β‐barrel proteins

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