The Biosynthesis of Vancomycin-Type Glycopeptide Antibiotics-A Model for Oxidative Side-Chain Cross-Linking by Oxygenases Coupled to the Action of Peptide Synthetases

ChemBioChem ◽  
2005 ◽  
Vol 6 (2) ◽  
pp. 267-272 ◽  
Author(s):  
Daniel Bischoff ◽  
Bojan Bister ◽  
Marcelo Bertazzo ◽  
Volker Pfeifer ◽  
Efthimia Stegmann ◽  
...  
Keyword(s):  
Side Chain ◽  
Cross Linking ◽  
Glycopeptide Antibiotics ◽  
Peptide Synthetases

Side-Chain Cholesteric Liquid Crystalline Elastomers Derived from a Mesogenic Cross-Linking Agent

2003 ◽  
Vol 36 (24) ◽  
pp. 9060-9066 ◽  
Author(s):  
Jian-She Hu ◽  
Bao-Yan Zhang ◽  
Ying-Gang Jia ◽  
Song Chen
Keyword(s):  
Liquid Crystalline ◽  
Side Chain ◽  
Cross Linking ◽  
Cholesteric Liquid Crystalline

Anionic Cross-Linking of Polymers Having an Epoxy Group in the Side Chain with Bicyclic and Spirocyclic Bis(γ-lactone)s

1997 ◽  
Vol 30 (9) ◽  
pp. 2532-2538 ◽  
Author(s):  
Keunwo Chung ◽  
Toshikazu Takata ◽  
Takeshi Endo
Keyword(s):  
Epoxy Group ◽  
Side Chain ◽  
Cross Linking

Study on Synthesis and Characterization of Unsaturated Polyester by Enzyme-Catalyzed

2013 ◽  
Vol 575-576 ◽  
pp. 67-70
Author(s):  
Fen Juan Shao ◽  
Qun Yang ◽  
Lan Ying Li ◽  
Da Nian Lu
Keyword(s):  
High Temperature ◽  
Unsaturated Polyester ◽  
Soxhlet Extraction ◽  
Side Chain ◽  
Synthesis And Characterization ◽  
Cross Linking ◽  
Cross Link ◽  
H Nmr ◽  
Ft Ir

Unsaturated polyester was prepared with adipic acid (AA), fumaric acid (FA), itaconic acid (IA) and 1, 6-hexanediol (HD) by enzyme-catalyzed polmerization. The insoluble gel fraction (Qs), as the cross-linking degree of cured unsaturated polyesters which could be self-cross-linked at high temperature through C=C in it, was got by Soxhlet Extraction. The properties were investigated by FT-IR, 1H NMR, DSC, XRD and so on. The results indicated that the C=C in unsaturated diacids reduced the acitvity of N435, which affected the polmerization. With the introduction of C=C of IA or FA, the Mn of polyester reduced. The C=C could self-cross-link under high temperature for lengthy time. The higher the temperature and the longer the time, the Qs increased. As the C=C of IA was in the side chain, it could move easily. Then Qs of poly (AA-co-IA-co-HD) was higher than ploy (AA-co-FA-co-HD). With the increased content of unsaturated diacid, Qs increased. And the biodegradation of cross-linked polyesters became worse.

Cross-Linking Behavior of Diskotic Side-Chain Polymers in Solution

2004 ◽  
Vol 37 (20) ◽  
pp. 7839-7845 ◽  
Author(s):  
Marcel W. C. P. Franse ◽  
Klaas te Nijenhuis ◽  
Jan Groenewold ◽  
Stephen J. Picken
Keyword(s):  
Side Chain ◽  
Cross Linking

scholarly journals Hexapeptide Derivatives of Glycopeptide Antibiotics: Tools for Mechanism of Action Studies

2002 ◽  
Vol 46 (8) ◽  
pp. 2344-2348 ◽  
Author(s):  
Norris E. Allen ◽  
Deborah L. LeTourneau ◽  
Joe N. Hobbs ◽  
Richard C. Thompson
Keyword(s):  
Micrococcus Luteus ◽  
Membrane Vesicles ◽  
Antibacterial Activities ◽  
Mechanisms Of Action ◽  
Side Chain ◽  
Bacterial Membrane ◽  
Glycopeptide Antibiotics ◽  
Bacterial Membranes ◽  
Derivatives Of

ABSTRACT Hexapeptide (des-N-methylleucyl) derivatives of LY264826 were prepared in order to examine further the role of N-substituted hydrophobic side chains in defining the mechanisms of action of semisynthetic glycopeptide antibiotics. The hexapeptide of LY264826 binds to the cell wall intermediate analog l-Lys-d-Ala-d-Ala with a 100-fold lower affinity than LY264826 and inhibits Micrococcus luteus almost 200-fold more poorly than LY264826 does. Alkylation of the 4-epi-vancosamine moiety of the disaccharide significantly enhanced the antibacterial activity of the hexapeptide. Alkylation did not affect the binding affinity for d-alanyl-d-alanine residues; however, it did enhance dimerization 7,000-fold and enhanced binding to bacterial membrane vesicles noticeably compared with the levels of dimerization and binding for the unsubstituted hexapeptide. The findings from this study complement those presented in an earlier report (N. E. Allen, D. L. LeTourneau, and J. N. Hobbs, Jr., J. Antibiot. 50:677-684, 1997) and are consistent with the conclusion that the enhanced antibacterial activities of semisynthetic glycopeptide antibiotics derive from the ability of the hydrophobic side chain to markedly affect both dimerization and binding to bacterial membranes.

Preparation of polyferrocenylsilane via thermal ROP, synthesis of polyferrocenylsilane with methacrylate side chain and its photochemical cross-linking properties

2006 ◽  
Vol 60 (11) ◽  
pp. 1416-1419 ◽  
Author(s):  
Jian-Jun Wang ◽  
Li Wang ◽  
Xue-Jie Wang ◽  
Tao Chen ◽  
Hao-Jie Yu ◽  
...  
Keyword(s):  
Side Chain ◽  
Cross Linking

Engineering oxidative stability in human hemoglobin based on the Hb providence (βK82D) mutation and genetic cross-linking

2017 ◽  
Vol 474 (24) ◽  
pp. 4171-4192 ◽  
Author(s):  
Michael Brad Strader ◽  
Rachel Bangle ◽  
Claire J. Parker Siburt ◽  
Cornelius L. Varnado ◽  
Jayashree Soman ◽  
...  
Keyword(s):  
Oxidative Degradation ◽  
Oxygen Affinity ◽  
Side Chain ◽  
Cross Linking ◽  
Critical Element ◽  
Low Oxygen ◽  
Naturally Occurring ◽  
Low Concentrations ◽  
Genetic Cross ◽  
Low Oxygen Affinity

Previous work suggested that hemoglobin (Hb) tetramer formation slows autoxidation and hemin loss and that the naturally occurring mutant, Hb Providence (HbProv; βK82D), is much more resistant to degradation by H2O2. We have examined systematically the effects of genetic cross-linking of Hb tetramers with and without the HbProv mutation on autoxidation, hemin loss, and reactions with H2O2, using native HbA and various wild-type recombinant Hbs as controls. Genetically cross-linked Hb Presbyterian (βN108K) was also examined as an example of a low oxygen affinity tetramer. Our conclusions are: (a) at low concentrations, all the cross-linked tetramers show smaller rates of autoxidation and hemin loss than HbA, which can dissociate into much less stable dimers and (b) the HbProv βK82D mutation confers more resistance to degradation by H2O2, by markedly inhibiting oxidation of the β93 cysteine side chain, particularly in cross-linked tetramers and even in the presence of the destabilizing Hb Presbyterian mutation. These results show that cross-linking and the βK82D mutation do enhance the resistance of Hb to oxidative degradation, a critical element in the design of a safe and effective oxygen therapeutic.

scholarly journals Tyrosine Metabolism in Blowfly Larvae at Pupation

1964 ◽  
Vol 17 (3) ◽  
pp. 803 ◽  
Author(s):  
RH Hackman KN Saxen
Keyword(s):  
Direct Evidence ◽  
Side Chain ◽  
Cross Linking ◽  
Cuticular Protein ◽  
Oxidative Deamination ◽  
Tyrosine Metabolism ◽  
Metabolic Reactions

In insects tyrosine has been regarded as participating in metabolic reactions which lead, not only to its incorporation in various proteins, but also to sclerotization of the cuticle (i.e. quinone cross-linking of cuticular protein). Three different meta-bolic pathways have been suggested, all of which lack direct evidence to support them. The suggested pathways are (i) oxidative deamination leading to the formation of o-quinones, (ii) non-specific hydroxylation and elimination of the side-chain leading to the formation of p-quinones, and (iii) conversion to N-acetyldopamine which is the phenolic precursor of the sclerotizing quinone. For a review of these theories see Pryor (1962) and Hackman (1964).

Helix-Constrained Peptides Constructed by Head-to-Side Chain Cross-Linking Strategies

2021 ◽  
Author(s):  
Xiao-Xu Chen ◽  
Yang Tang ◽  
Meng Wu ◽  
Yan-Ni Zhang ◽  
Kai Chen ◽  
...  
Keyword(s):  
Side Chain ◽  
Cross Linking ◽  
Constrained Peptides
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