Of poly-L-lysine

Several years ago Makino et al. 86) studied the influence of anions on the conformation of poly-[L-methionine-S-methylsulfonium] salts in solution. They found that especially perchlorate will induce a-helix formation whereas Cl- and Br do not. Since then several authors 87 92) have found a similar a-helix inducing effect in the case of poly-L-lysine (Lys) and other BPAA at low pH-values where the polymer molecules usually attain an extended conformation due to the electrostatic repulsion of the ammonium groups. Therefore, the a-helix inducing effect is obviously an... 

Fig. 3. Backscattered Raman (/R + /L) and ROA (/R — /L) spectra of poly-L-lysine in o -helical (top pair) and disordered (second pair) conformations, and of poly-L-glutamic acid in a-helical (third pair) and disordered (bottom pair) conformations in aqueous solution. Reprinted from Barron et al., 2000, Prog. Biophys. Mol. Biol. 73, 1-49, with permission from Elsevier Science.

Fig. 1. Comparison of amide V VCD for an identical sample of poly-L-lysine in D20 as measured on the UIC dispersive instrument (top) and on the ChirallRFT-VCD instrument (at Vanderbilt University, kindly made available by Prof. Prasad Polavarapu). Sample spectra were run at the same resolution for the same total time ( 1 h) in each case. The FTIR absorbance spectrum of the sample is shown below. VCD spectra are offset for sake of comparison. Each ideal baseline is indicated by a thin line, the scale providing a measure of amplitude. Noise can be estimated as the fluctuation in the baseline before and after the amide V, which indicates the S/N advantage of the single band dispersive measurement.

M 0004. (From Tiffany and Krimm, 1969, Biopolymers 8, 347-359, 1969. Reprinted by permission of John Wiley Sons, Inc.) (B) CD spectrum of poly-L-proline II (sigma, molecular weight 55,000) as a function of temperature. (C) CD spectrum of polyglutamic acid at pH 7 as a function of temperature. (D) CD spectrum of poly-L-lysine at pH 7 as a function of temperature. Parts (B-D) are from Tiffany and Krimm (1972). Biopolymers 11, 2309-2316, 1972. Reprinted by permission of John Wiley 8c Sons, Inc. 

Fig. 26. (A) The backscattered Raman and ROA spectra of poly-L-lysine in o -helical...

Multiblock copolymers of poly(L-lysine) and PEG were prepared following the reaction sequence illustrated in Scheme 66. N-carboxy-(AT -benzyloxy... 

Transition-metal phosphorus trichalcogenides such as MnPS3 are able to intercalate amino acids and peptides by ion exchange. In this way, increases in the basal spacing of 0.7 and 3-4 nm are observed for the intercalation of poly-L-lysine and lysozyme, respectively [224]. Interestingly, the enzymatic activity of the immobilized protein has been detected, suggesting that the enzyme is protected against denaturation. 

Patwardhan, S.V., Mukherjee, N. and Clarson, S.J. (2001) The use of poly-L-lysine to form novel silica morphologies and the role of polypeptides in biosilicification. Journal of Inorganic and Organometcdlic Polymers, 11, 193-198. 

Fig. 57. Tris(2-ethylamino)amine (8) used as central core for the build up of poly-L-lysine cellobioside dendrimers. ... 

Xu B, Wiehle S, Roth JA, Cristiano RJ (1998) The contribution of poly-L-lysine, epidermal growth factor and streptavidin to EGF/PLL/DNA polyplex formation. Gene Ther... 

Muller M, Reihs T, Ouyang W (2005) Needlelike and spherical polyelectrolyte complex nanoparticles of poly(L-lysine) and copolymers of maleic acid. Langmuir 21 465 -69... 

The grating-coupled nanoporous-silica-supported reverse waveguide chip was also applied for monitoring the attachment and spreading of Human Dermal Fibroblast cells to the surface16. As in the bacteria experiments, the waveguide surface was coated with a thin layer of poly-L-lysine layer to improve cell attachment and spreading. 

Synthesis of Poly-L-Lysine Containing Nucleic Acid Bases... 

The derivatives of poly-L-lysine having pendant nucleic acid bases, that is, adenine, thymine and uracil were prepared as shown in the following scheme ... 

The spectral data of these polymers are tabulated in Table 1 and 2. From these data, it was concluded that the activated ester of Ade-PNP (2) reacted only with e-amino group of poly-L-lysine, and did not react with amino group of the adenine base. Figure 1, 2 and 3 show their NMR spectra. 

In relation to these works, the reaction of p-nitrophenyl esters with optically active poly( propyleneimine )(8) was studied at 25°C in DMSO solution according to the same procedure described for the case of poly-L-lysine derivatives. The poly( propyleneimine ) derivatives thus obtained have different IR and UV absorption spectra from those of the starting compounds, and show absorptions assigned to the nucleic acid bases. However, their contents determined by UV spectroscopy were substantially low as compared with the case of poly-L-lysine derivatives for (9) and (20), the base contents were below 30 and 50 %, respectively. The result was explained by a steric hindrance caused by methyl groups on the main chain of poly( propyleneimine ) ... 

Liu, G., M. Molas, G. A. Grossmann, M. Pasumarthy, J. C. Perales, M. J. Cooper, and R. W. Hanson. 2001. Biological properties of poly-L-lysine-DNA complexes generated by cooperative binding of the polycation. J Biol Chem 276(37) 34379-87. 

Capan Y, Woo BH, Gebrekidan S, et al. Stability of poly(L-lysine)-complexed plasmid DNA during mechanical stress and DNase I treatment. Pharm Dev Technol 1999 4(4) 491-498. 

Wolfert MA, Seymour LW. Atomic force microscopic analysis of the influence of the molecular weight of poly(L)lysine on the size of polyelectrolyte complexes formed with DNA. Gene Ther 1998 3(3) 269-273. 

Pretreat the wells of the 96-well plate with 100 pL of poly-L-lysine in PBS for 1-16 h at room temperature. 

Mechanistic Ideas. The ordinary-extraordinary transition has also been observed in solutions of dinucleosomal DNA fragments (350 bp) by Schmitz and Lu (12.). Fast and slow relaxation times have been observed as functions of polymer concentration in solutions of single-stranded poly(adenylic acid) (13 14), but these experiments were conducted at relatively high salt and are interpreted as a transition between dilute and semidilute regimes. The ordinary-extraordinary transition has also been observed in low-salt solutions of poly(L-lysine) (15). and poly(styrene sulfonate) (16,17). In poly(L-lysine), which is the best-studied case, the transition is detected only by QLS, which measures the mutual diffusion coefficient. The tracer diffusion coefficient (12), electrical conductivity (12.) / electrophoretic mobility (18.20.21) and intrinsic viscosity (22) do not show the same profound change. It appears that the transition is a manifestation of collective particle dynamics mediated by long-range forces but the mechanistic details of the phenomenon are quite obscure. 

Aleksina et al. investigating polymerization of methacrylic acid in the presence of poly-L-lysine found that the complex obtained by template polymerization has a 1 1 stoichiometry, while the same components obtained by separation of the complex and repeated mixing gave a complex in which the ratio of polylysine units to polyacid units is 2 3. The stable conformation of polylysine macromolecule in the complex obtained by template polymerization is the conformation of a-helix. 

As a result of specific interactions, molecules of one component are surrounded by molecules of the second component in the segments of helix form. On the basis of these findings it is possible to assume that similar structures are formed during polymerization of methyl methacrylate in the presence of the isotactic template, or polymerization of methacrylic acid in the presence of poly(L-lysine). However, more experimental results are still needed. 

Malin et al. (1989) reported deamination of e-amino groups of lysine in proteins tteated at pH 3.0 with high levels of nitrite. They reported deamination of 13% of the e-amino groups of poly-L-lysine at pH 5.5—6.4 during a 24-hr period, suggesting the possibility for some loss of available lysine in slightly acid, nitrite-treated foods. However, protein-lysyl groups are not a site for formation of protein-bound nitrite, since Nj gas was released as a result of lysine deamination. 

Steric stabilization of poly-l-lysine/DNA complexes by the covalent attachment of semitelechelic poly [A-(2-hydroxypropyl)methacrylamide]. Bioconjugate Chem., 11, 492-501. 

The metalloporphyrin complexes and their derivatives have been studied from the standpoint of model compounds of hemoglobin. The polymer-metalloporphyrin complexes are also formed by the reaction in Scheme 8, and a few qualitative investigations have been made with poly(L-lysine)9,10, poly(L-histidine)11, and poly(vinylimidazole)12 as the polymer ligand. Blauer9 has studied the complex formation of heme with poly(L-lysine) and has discussed the effects of the molecular weight and secondary structure of poly(L-lysine) on complex formation. 

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