- Synthesis, characterization and in vitro photodynamic antimicrobial activity of basic amino acid-porphyrin conjugates
-
Photodynamic antimicrobial chemotherapy (PACT), as a novel and effective modality for the treatment of infection with the advantage of circumventing multidrug resistance, receives great attention in recent years. The photosensitizer is the crucial element in PACT, and cationic porphyrins have been demonstrated to usually be more efficient than neutral and negatively charged analogues towards bacteria in PACT. In this work, three native basic amino acids, l-lysine, l-histidine and l-arginine, were conjugated with amino porphyrins as cationic auxiliary groups, and 13 target compounds were synthesized. This paper reports their syntheses, structural characterizations, oil-water partition coefficients, singlet oxygen generation yields, photo-stability, as well as their photo inactivation efficacies against methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Pseudomonas aeruginosa in vitro. The preliminary structure-activity relationship was discussed. Compound 4i, with porphyrin bearing four lysine moieties, displays the highest photo inactivation efficacy against the tested bacterial strains at 3.91 1/4M with a low light dose (6 J/cm2), and it is stable in serum and lower cytotoxicity to A929 cells. These basic amino acid-porphyrin conjugates are potential photosensitizers for PACT.
- Meng, Shuai,Xu, Zengping,Hong, Ge,Zhao, Lihui,Zhao, Zhanjuan,Guo, Jianghong,Ji, Haiying,Liu, Tianjun
-
-
Read Online
- Two Distinct Mechanisms for C-C Desaturation by Iron(II)- and 2-(Oxo)glutarate-Dependent Oxygenases: Importance of α-Heteroatom Assistance
-
Hydroxylation of aliphatic carbons by nonheme Fe(IV)-oxo (ferryl) complexes proceeds by hydrogen-atom (H?) transfer (HAT) to the ferryl and subsequent coupling between the carbon radical and Fe(III)-coordinated oxygen (termed rebound). Enzymes that use H?-abstracting ferryl complexes for other transformations must either suppress rebound or further process hydroxylated intermediates. For olefin-installing C-C desaturations, it has been proposed that a second HAT to the Fe(III)-OH complex from the carbon α to the radical preempts rebound. Deuterium (2H) at the second site should slow this step, potentially making rebound competitive. Desaturations mediated by two related l-arginine-modifying iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) oxygenases behave oppositely in this key test, implicating different mechanisms. NapI, the l-Arg 4,5-desaturase from the naphthyridinomycin biosynthetic pathway, abstracts H? first from C5 but hydroxylates this site (leading to guanidine release) to the same modest extent whether C4 harbors 1H or 2H. By contrast, an unexpected 3,4-desaturation of l-homoarginine (l-hArg) by VioC, the l-Arg 3-hydroxylase from the viomycin biosynthetic pathway, is markedly disfavored relative to C4 hydroxylation when C3 (the second hydrogen donor) harbors 2H. Anchimeric assistance by N6 permits removal of the C4-H as a proton in the NapI reaction, but, with no such assistance possible in the VioC desaturation, a second HAT step (from C3) is required. The close proximity (≤3.5 ?) of both l-hArg carbons to the oxygen ligand in an X-ray crystal structure of VioC harboring a vanadium-based ferryl mimic supports and rationalizes the sequential-HAT mechanism. The results suggest that, although the sequential-HAT mechanism is feasible, its geometric requirements may make competing hydroxylation unavoidable, thus explaining the presence of α-heteroatoms in nearly all native substrates for Fe/2OG desaturases.
- Dunham, Noah P.,Chang, Wei-Chen,Mitchell, Andrew J.,Martinie, Ryan J.,Zhang, Bo,Bergman, Jonathan A.,Rajakovich, Lauren J.,Wang, Bo,Silakov, Alexey,Krebs, Carsten,Boal, Amie K.,Bollinger, J. Martin
-
-
Read Online
- The synthesis of a lipophilic derivative of RGD peptide
-
Bishexadecyl ester of RGD peptide was synthesized in solution by the conventional methods of peptide chemistry in a total yield of 48%.
- Stepanenko,Sebyakin
-
-
Read Online
- Quinone-amino acid conjugates targeting leishmania amino acid transporters
-
The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7) to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III) with amino acids (i.e. arginine and lysine) by means of an amide linkage. The toxicity of the synthesized conjugates against Leishmania extracellular (promastigotes) and intracellular (amastigotes) forms was investigated, as well their inhibition of the relevant amino acid transporters. We observed that some conjugates indeed displayed toxicity against the parasites; in particular, 7 was identified as the most potent derivative (at concentrations of 1 μg/mL and 2.5 μg/mL residual cell viability was reduced to 15% and 48% in promastigotes and amastigotes, respectively). Notably, 6, while retaining the cytotoxic activity of quinone II, displayed no toxicity against mammalian THP1 cells. Transport assays indicated that the novel conjugates inhibited transport activity of lysine, arginine and proline transporters. Furthermore, our analyses suggested that the toxic conjugates might be translocated by the transporters into the cells. The non-toxic probes that inhibited transport competed with the natural substrates for binding to the transporters without being translocated. Thus, it is likely that 6, by exploiting amino acid transporters, can selectively deliver its toxic effects to Leishmania cells. This work provides the first evidence that amino acid transporters of the human pathogen Leishmania might be modulated by small molecules, and warrants their further investigation from drug discovery and chemical biology perspectives.
- Prati, Federica,Goldman-Pinkovich, Adele,Lizzi, Federica,Belluti, Federica,Koren, Roni,Zilberstein, Dan,Bolognesi, Maria Laura
-
-
Read Online
- MODULATION OF IMMUNE CELLS
-
Disclosed are immune cell-selective small molecule IMPDH inhibitor compounds and methods of their synthesis and use to treat proliferative disorders.
- -
-
Paragraph 0050; 00142-00143
(2021/08/06)
-
- Rhamnolipid inspired lipopeptides effective in preventing adhesion and biofilm formation of Candida albicans
-
Rhamnolipids are biodegradable low toxic biosurfactants which exert antimicrobial and anti-biofilm properties. They have attracted much attention recently due to potential applications in areas of bioremediation, therapeutics, cosmetics and agriculture, however, the full potential of these versatile molecules is yet to be explored. Based on the facts that many naturally occurring lipopeptides are potent antimicrobials, our study aimed to explore the potential of replacing rhamnose in rhamnolipids with amino acids thus creating lipopeptides that would mimic or enhance properties of the parent molecule. This would allow not only for more economical and greener production but also, due to the availability of structurally different amino acids, facile manipulation of physico-chemical and biological properties. Our synthetic efforts produced a library of 43 lipopeptides revealing biologically more potent molecules. The structural changes significantly increased, in particular, anti-biofilm properties against Candida albicans, although surface activity of the parent molecule was almost completely abolished. Our findings show that the most active compounds are leucine derivatives of 3-hydroxy acids containing benzylic ester functionality. The SAR study demonstrated a further increase in activity with aliphatic chain elongation. The most promising lipopeptides 15, 23 and 36 at 12.5 μg/mL concentration allowed only 14.3%, 5.1% and 11.2% of biofilm formation, respectively after 24 h. These compounds inhibit biofilm formation by preventing adhesion of C. albicans to abiotic and biotic surfaces.
- Jovanovic, Milos,Radivojevic, Jelena,O'Connor, Kevin,Blagojevic, Stevan,Begovic, Biljana,Lukic, Vera,Nikodinovic-Runic, Jasmina,Savic, Vladimir
-
supporting information
p. 209 - 217
(2019/03/23)
-
- N,N,N-Tris(tert-butoxycarbonyl)-l-arginine: five isoforms whose obtainment depends on procedure and scrupulous NMR confirmation of their structures
-
l-arginine is often covalently linked to vectors for gene or drug delivery as a means of increasing their transfection activity and reducing toxicity. This strategy relies on the protection of basic nitrogen atoms, for example, by employing the tert-butoxycarbonyl group. Our aim in the present work was to prepare the widely described αN,ωN,ω′N-tris(tert-butyloxycarbonyl)-l-arginine as a single isomer in high yield and with high levels of purity for use in the esterification of dendrimers with several peripheral hydroxyl groups. Following three reported protocols which assured this goal, we observed the unexpected formation of four additional isomers. Using the first procedure, αN,ωN,ω′N-tris(tert-butyloxycarbonyl)-l-arginine was never obtained. The second procedure delivered the desired compound as a mixture of geometric isomers (E/Z), while the third protocol led to a single isomer in high yield and purity, but with an unreported symmetrical structure. Since Boc protection is transient, this discovery would seem to be of little interest, but preliminary results from an ongoing investigation of the behavior of each of the isomers obtained in the esterification reactions of interest has shown that their reactivity depends on their structure. Although this research is ongoing, here we report a detailed description of these unexpected results, along with an NMR investigation focusing on the double-bond geometry and position which enabled confirmation of the structures.
- Alfei, Silvana,Castellaro, Sara
-
p. 1811 - 1832
(2017/12/04)
-
- COMPOUNDS, COMPOSITONS AND METHODS RELATED TO ANTIMICROBIAL APPLICATIONS
-
The present disclosure is in the field of polymers and pharmaceuticals/antimicrobials. The disclosure provides compounds based on SNAP (synthetic novel antimicrobial polymer) technology, compositions and methods of managing microbial infections including surgical site infections (SSIs). The present compounds are used as a management/therapeutic strategy to target microbial infections and have advantages including excellent antimicrobial potency, biofilm disruption ability, broad spectrum activity against various organisms covering both gram negative and gram positive bacteria as well as fungal pathogens, and low toxicity profile to ensure a healthy therapeutic window for use in humans.
- -
-
Page/Page column 78-79
(2018/03/25)
-
- COMPOSITIONS AND METHODS FOR THE TREATMENT OF METABOLIC DISEASES
-
The invention relates to the compounds of formula I, formula II and formula III or its pharmaceutical acceptable salts, as well as polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compounds of formula I, formula II or formula III; and methods for treating or preventing metabolic diseases may be formulated for oral, buccal, rectal, topical, transdermal, transmucosal, intravenous, parenteral administration, syrup, or injection. Such compositions may be used to treatment of phenylketonuria, cardiovascular disease, autism, ADHD, hypertension, endothelial dysfunction and chronic kidney disease.
- -
-
Paragraph 0168; 0187; 0188
(2015/11/18)
-
- Synthesis and identification of proposed biosynthetic intermediates of saxitoxin in the cyanobacterium Anabaena circinalis (TA04) and the dinoflagellate Alexandrium tamarense (Axat-2)
-
Here, we describe the synthesis of the genetically predicted biosynthetic intermediates of the neurotoxin saxitoxin (STX) (1), 2, 6 and 7, and identification of 2 and 6 in toxin-producing microorganisms. This is the first chemical evidence supporting the
- Tsuchiya, Shigeki,Cho, Yuko,Konoki, Keiichi,Nagasawa, Kazuo,Oshima, Yasukatsu,Yotsu-Yamashita, Mari
-
supporting information
p. 3016 - 3020
(2014/05/06)
-
- Total synthesis of miraziridine A and identification of its major reaction site for cathepsin B
-
The synthesis of miraziridine A, a pentapeptide derivative isolated from marine sponge, and its truncated analogs has been achieved. To construct the backbone of miraziridine A, a side-chain-unprotected vinylogous arginine was condensed with an aziridine-
- Konno, Hiroyuki,Kubo, Kanako,Makabe, Hidefumi,Toshiro, Emi,Hinoda, Naoyuki,Nosaka, Kazuto,Akaji, Kenichi
-
p. 9502 - 9513
(2008/02/12)
-
- Synthesis and biological evaluation of two chemically modified peptide epitopes for the class i MHC protein HLA-B*2705
-
The T-cell receptor of a CD8+ T-cell recognises peptide epitopes bound by class I major histocompatibility complex (MHC) glycoproteins presented in a groove on their upper surface. Within the groove of the MHC molecule are 6 pockets, two of whi
- Jones, Matthew A.,Hislop, Andrew D.,Snaith, John S.
-
p. 3769 - 3777
(2008/09/18)
-
- Synthesis of barettin
-
The indole alkaloid barettin (with bromine in 6-position), isolated from the marine sponge Geodia Barretti, has been synthesised via a Horner-Wadsworth-Emmons type reaction from 6-bromoindole-3-carboxaldehyde to introduce the dehydro-functionality. Subsequent deprotection and cyclisation afforded the natural product in Z-conformation.
- Johnson, Ann-Louise,Bergman, Jan,Sj?gren, Martin,Bohlin, Lars
-
p. 961 - 965
(2007/10/03)
-