Poly-D-glutamic acid

Contains poly-D-glutamic acid capsule, essential for virulence and avoidance of immune detection... 

KIshore BK, Lambricht P, Laurent G, Maldague P, Wagner R,Tulkens PM, Mechanism of protection afforded by polyaspartic acid against gentamicin-Induced phosphollpidosis. II. Comparative In-vltroand In-vivo studies with poly-L-aspartIc, poly-L-glutamIc and poly-D-glutamIc acids, J Pharmacol ExpTherap, 1990,255(2) 875-85. 

Poly( a-amino acid/vis a better term for peptides formed by the self-condensation of one amino acid natural examples exist, such as poly(D-glutamic acid), the protein coat of the anthrax spore (Flanby and Rydon, 1946). In early research in the textile industry, poly(a-amino acid)s showed promise as synthetic fibres, but the synthesis methodology required for the polymerisation of amino acids was complex and uneconomic. 

A special case of stepwise amino acid addition is repeated condensation to arrive at polymer structures. Such systems functioning in analogy to. for example, polyhydroxybu-tyrate-forming enzymes produce, for example, poly-D-glutamic acids (40,41), and they presumably are related to the polyenzyme type of peptide synthetases. These enzymes, condensing 3-carboxyl-groups, produce a size-defined polymer of about 10 Da. Other systems may produce poly-Lys chains of much smaller size, 25 residues (42). Even branched peptide-forming systems have been reported (43). None of these systems has been characterized in detail. 

The conformation of stendomycin was studied by circular dichroism. In trifluoroethanol the circular dichroism pattern was almost identical with that of left-handed a-helical poly-D-glutamic acid in water at pH 3.9 the amplitude was half that of poly-D-glutamic acid. The presence of a-helical zones in stendomycin was supported by the occurrence... 

Poly(D-glutamic acid) y-benzyl-chloro-meta (253.68) ortho para... 

Poly(D-glutamic acid), sodium salt 30811-79-1 D-Glutamic acid, homopolymer, sodium salt R (C,H9N04),- jtNa... 

Fig. 5. The helix-coil transition of poly(D-glutamic acid) as revealed by conductance-transference. Solid lines are the limiting laws for/, Equation (102), for the helical structure = 4.75 a, and the coil structure, < = 1.98 a, a being the degree of neutralization. Conductance-transference data (open...

King EC, Watkins WJ, Blacker AJ et al (1998) Covalent modification in aqueous solution of poly-y-D-glutamic acid from Bacillus licheniformis. J Polvin Sci A Polym Chem 36 1995-1999... 

Prodhomme EJF, Tutt AL, Glennie MJ et al (2003) Multivalent conjugates of poly-y-D-glutamic acid from Bacillus licheniformis with antibody F(ab ) and glycopeptide ligands. Bioconjug Chem 14 1148-1155... 

Schneerson R, Kubler-Kielb J, Liu TY et al (2003) Poly(y-D-glutamic acid) protein conjugates induce IgG antibodies in mice to the capsule of Bacillus anthracis a potential addition to the anthrax vaccine. Proc Natl Acad Sci USA 100 8945-8950... 

Joyce J, Cook J, Chabot D et al (2006) Immunogenicity and protective efficacy of Bacillus anthracis poly-y-D-glutamic acid capsule covalently coupled to a protein carrier using a novel triazine-based conjugation strategy. J Biol Chem 281 4831 -843... 

Kubler-Kielb J, Liu TY, Mocca C et al (2006) Additional conjugation methods and immunogenicity of Bacillus anthracis poly-y-D-glutamic acid-protein conjugates. Infect Immun 74 4744 1749... 

In a more recent study using circular dichroism, Pflumm and Beychok (313) have fitted the observed curve for RNase-A (see Figs. 11c and d) weighted mixtures of the characteristic bands for helix from poly-L-glutamic acid and / structure from poly-L-lysine. The data are compatible with 11.5% helix and 33% / conformation. Ribonuclease-S and RNase-A have almost identical CD spectra from 198 to 300 nm. The spectrum of S-protein is markedly different from the other two. 

The synthetic polyamino acids are convenient models for chemical studies of proteins since they have the extended polypeptide structure of the proteins but are free from the complications which arise in the proteins from the large number of different side chains. The work described here has been confined to the water-soluble polyamino acids poly-D,L-alanine (PDLA), poly-a,L-glutamic acid (PGA), poly-a,D-glutamic acid, and poly-a,L-lysine, and the polyimino acid, poly-L-proline. 

D-Glutamic acid has been detected in samples of poly-a,L-glutamic acid (PGA) irradiated in 1% solution at pH 6.8 (Na salt). The D-glutamic acid was measured in hydrolyzates of the polymer by an enzymic method 36). A specific enzyme, L-glutamate decarboxylase E. coli), converts L-glutamic... 

The yield of D-glutamic acid from poly-a,L-glutamic acid was very low in the presence of O2 (1 atm.). This can be accounted for by either of the mechanisms discussed above since O2 can combine both with H atoms and with the free radicals formed at the a-carbon atom (see Reactions 20-27). 

O. Pieroni, A. Fissi, F. Ciardelli, and D. Fabbri, Spiropyran-containing poly(L-glutamic acid). Photochromic and conformational behavior in acid conditions, Mol. Cryst. Liq. Cryst., 246, 191-194 (1994). 

Li, C. Yu, D.-R Newman, R. A. Cabral, P. Stephens, L. C. Milas, L. Wallace, S. Complete regression of well-established tumors using a novel water-soluble poly(L-glutamic acid)-paclitaxel conjugate. Cancer Res., 1998, 58 2404—2409. 

Thus it is now clear that the polyglutamic acids produced by B. subtilis and B. anthracis are entirely poly-7-D-glutamic acid. 

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