The conformation of poly‐L‐tyrosine in solution

Abstract

The optical and rotatory properties of poly-L-tyrosine (PLT) dissolved in trimethyl phosphate and in water have been measured.The results, however, cannot be explained in terms of one conformation or another, since the side-chains chromophores interact with the peptide groups or among themselves, thus giving rise to complex circular dichroic spectra.I R measurements carried out on films of PLT cast from trimethylphasphate (FMP) or directly on solutions of the polymer in TMP strongly suggest that the polypeptide assumes an a-helical conformation.The sense of spiralizaCon of the helix cannot be obtained with such measurements. ZUSAMMENFASSUNG:Es wurden die optischen und polarimetrischen Eigenschaften von Poly-L-tyrosin (PLT) in Trimethylphosphat und Wasser als Losungsmittel untersucht.Die Ergebnisse konnen jedoch nicht durch das Vorliegen einer bestimmten Konformation gedeutet werden, da Wechselwirkungen der Seitenketten-Chromophore mit sich selbst oder mit Peptidgruppen zu komplexen CD-Spektren fiihren.IR-Messungen an Filmen von PLT, die aus Trimethylphosphat (TMP) gegossen waren, oder direkt an Losungen des Polymeren in TMP machen wahrscheinlich, da13 das Polypeptid eine a-helikale Konformation ausbildet.Der Helixsinn kann aus solchen Messungen jedoch nicht bestimmt werden.

Comparative study of semiempirical methods for calculating interactions between large molecules with an application to the actinomycin-Guanine complex

“…It is not until the 6-binding sites are almost totally occupied that binding to the 4-binding site occurs. It should be noted, however, that this system may not be fully representative of actinomycin-DNA binding, which is an entropy driven process, having a total enthalpy of +2 kcal/mol [39].…”

Conformation and Conformational Transitions of Poly-α-Amino Acids in Solution

“…The difficulties involved are illustrated below in the ease of poly-L-tyrosine. In the near uv region, helical polytyrosine shows two positive (270 and 248 nm) and one negative (224 nm) bands (83,85,236,237,(243)(244)(245)(246)(247)(248)(249)(250)(251). Analysis of these data led to the suggestion that the sense of the polytyrosine helix is right-handed.…”

Poly(colloid)s: “Polymerization” of Poly(l-tyrosine)-silica Composite Particles through the Photoinduced Cross-Linking of Unmodified Proteins Method

“…In addition to enabling light-driven and enzymatically cross-linked colloids, PTYR exhibits an appealing variety of secondary structures. In organic solvents such as dimethylformamide, free, untethered PTYR assumes an α-helical conformation, − while in aqueous solution PTYR displays predominantly an antiparallel β-sheet conformation. − The addition of aqueous NaOH induces a transition from α-helix to β-sheet. , PTYR undergoes a coil-to-helix transition in the presence of dichloroacetic acid . PTYR tethered to a colloidal core is expected to display similar behavior in terms of conformational transitions, as reflected in optical and dimension changes at appropriate molecular weight of the shell.…”