scholarly journals Biosynthesis and Ether‐Bridge Formation in Nargenicin Macrolides

2019 ◽  
Vol 131 (12) ◽  
pp. 4036-4041 ◽  
Author(s):  
Sacha J. Pidot ◽  
Marion Herisse ◽  
Liam Sharkey ◽  
Liselle Atkin ◽  
Jessica L. Porter ◽  
...  
Keyword(s):  
Bridge Formation ◽  
Ether Bridge

scholarly journals Biosynthesis and Ether‐Bridge Formation in Nargenicin Macrolides

2019 ◽  
Vol 58 (12) ◽  
pp. 3996-4001 ◽  
Author(s):  
Sacha J. Pidot ◽  
Marion Herisse ◽  
Liam Sharkey ◽  
Liselle Atkin ◽  
Jessica L. Porter ◽  
...  
Keyword(s):  
Bridge Formation ◽  
Ether Bridge

Demonstration of methylene-ether bridge formation in melamine-formaldehyde resins

1995 ◽  
Vol 33 (6) ◽  
pp. 915-920 ◽  
Author(s):  
M. L. Scheepers ◽  
P. J. Adriaensens ◽  
J. M. Gelan ◽  
R. A. Carleer ◽  
D. J. Vanderzande ◽  
...  
Keyword(s):  
Melamine Formaldehyde ◽  
Bridge Formation ◽  
Ether Bridge ◽  
Methylene Ether

scholarly journals Ether bridge formation in loline alkaloid biosynthesis

2014 ◽  
Vol 98 ◽  
pp. 60-68 ◽  
Author(s):  
Juan Pan ◽  
Minakshi Bhardwaj ◽  
Jerome R. Faulkner ◽  
Padmaja Nagabhyru ◽  
Nikki D. Charlton ◽  
...  
Keyword(s):  
Alkaloid Biosynthesis ◽  
Bridge Formation ◽  
Ether Bridge

Introductory Remarks

1980 ◽  
Vol 38 ◽  
pp. 598-599
Author(s):  
H. Mohri
Keyword(s):  
Muscle Contraction ◽  
Experimental Evidence ◽  
Sea Urchin ◽  
Constant Length ◽  
Thin Filaments ◽  
Bridge Formation ◽  
Thick Filaments ◽  
Sliding Mechanism ◽  
Radial Spokes ◽  
Cilia And Flagella

In 1959, Afzelius observed the presence of two rows of arms projecting from each outer doublet microtubule of the so-called 9 + 2 pattern of cilia and flagella, and suggested a possibility that the outer doublet microtubules slide with respect to each other with the aid of these arms during ciliary and flagellar movement. The identification of the arms as an ATPase, dynein, by Gibbons (1963)strengthened this hypothesis, since the ATPase-bearing heads of myosin molecules projecting from the thick filaments pull the thin filaments by cross-bridge formation during muscle contraction. The first experimental evidence for the sliding mechanism in cilia and flagella was obtained by examining the tip patterns of molluscan gill cilia by Satir (1965) who observed constant length of the microtubules during ciliary bending. Further evidence for the sliding-tubule mechanism was given by Summers and Gibbons (1971), using trypsin-treated axonemal fragments of sea urchin spermatozoa. Upon the addition of ATP, the outer doublets telescoped out from these fragments and the total length reached up to seven or more times that of the original fragment. Thus, the arms on a certain doublet microtubule can walk along the adjacent doublet when the doublet microtubules are disconnected by digestion of the interdoublet links which connect them with each other, or the radial spokes which connect them with the central pair-central sheath complex as illustrated in Fig. 1. On the basis of these pioneer works, the sliding-tubule mechanism has been established as one of the basic mechanisms for ciliary and flagellar movement.

scholarly journals Influence of pH, Temperature and Protease Inhibitors on Kinetics and Mechanism of Thermally Induced Aggregation of Potato Proteins

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 796
Author(s):  
David J. Andlinger ◽  
Pauline Röscheisen ◽  
Claudia Hengst ◽  
Ulrich Kulozik
Keyword(s):  
Protein Interactions ◽  
Disulfide Bonds ◽  
Food Systems ◽  
Disulfide Bridge ◽  
Food Protein ◽  
Potato Protein ◽  
Covalent Bonds ◽  
Bridge Formation ◽  
Induced Aggregation ◽  
Influence Of Ph

Understanding aggregation in food protein systems is essential to control processes ranging from the stabilization of colloidal dispersions to the formation of macroscopic gels. Patatin rich potato protein isolates (PPI) have promising techno-functionality as alternatives to established proteins from egg white or milk. In this work, the influence of pH and temperature on the kinetics of PPI denaturation and aggregation was investigated as an option for targeted functionalization. At a slightly acidic pH, rates of denaturation and aggregation of the globular patatin in PPI were fast. These aggregates were shown to possess a low amount of disulfide bonds and a high amount of exposed hydrophobic amino acids (S0). Gradually increasing the pH slowed down the rate of denaturation and aggregation and alkaline pH levels led to an increased formation of disulfide bonds within these aggregates, whereas S0 was reduced. Aggregation below denaturation temperature (Td) favored aggregation driven by disulfide bridge formation. Aggregation above Td led to fast unfolding, and initial aggregation was less determined by disulfide bridge formation. Inter-molecular disulfide formation occurred during extended heating times. Blocking different protein interactions revealed that the formation of disulfide bond linked aggregation is preceded by the formation of non-covalent bonds. Overall, the results help to control the kinetics, morphology, and interactions of potato protein aggregation for potential applications in food systems.

scholarly journals Piper nigrum CYP719A37 Catalyzes the Decisive Methylenedioxy Bridge Formation in Piperine Biosynthesis

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 128
Author(s):  
Arianne Schnabel ◽  
Fernando Cotinguiba ◽  
Benedikt Athmer ◽  
Thomas Vogt
Keyword(s):  
Ferulic Acid ◽  
Functional Expression ◽  
Black Pepper ◽  
Amide Bond ◽  
Chain Elongation ◽  
Piper Nigrum ◽  
Yeast Saccharomyces Cerevisiae ◽  
Bridge Formation ◽  
Phylogenetic Origin ◽  
Catalyzed Reactions

Black pepper (Piper nigrum) is among the world’s most popular spices. Its pungent principle, piperine, has already been identified 200 years ago, yet the biosynthesis of piperine in black pepper remains largely enigmatic. In this report we analyzed the characteristic methylenedioxy bridge formation of the aromatic part of piperine by a combination of RNA-sequencing, functional expression in yeast, and LC-MS based analysis of substrate and product profiles. We identified a single cytochrome P450 transcript, specifically expressed in black pepper immature fruits. The corresponding gene was functionally expressed in yeast (Saccharomyces cerevisiae) and characterized for substrate specificity with a series of putative aromatic precursors with an aromatic vanilloid structure. Methylenedioxy bridge formation was only detected when feruperic acid (5-(4-hydroxy-3-methoxyphenyl)-2,4-pentadienoic acid) was used as a substrate, and the corresponding product was identified as piperic acid. Two alternative precursors, ferulic acid and feruperine, were not accepted. Our data provide experimental evidence that formation of the piperine methylenedioxy bridge takes place in young black pepper fruits after a currently hypothetical chain elongation of ferulic acid and before the formation of the amide bond. The partially characterized enzyme was classified as CYP719A37 and is discussed in terms of specificity, storage, and phylogenetic origin of CYP719 catalyzed reactions in magnoliids and eudicots.

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