Substrate Specificity of the Glycosyl Donor for Oligosaccharyl Transferase

2001 ◽  
Vol 66 (19) ◽  
pp. 6217-6228 ◽  
Author(s):  
Vincent W.-F. Tai ◽  
Barbara Imperiali
2002 ◽  
Vol 55 (2) ◽  
pp. 3 ◽  
Author(s):  
S. J. Williams ◽  
S. G. Withers

Glycosynthases are engineered mutant glycosidases that catalyse the formation of a glycosidic bond from a glycosyl donor and an acceptor alcohol. They are constructed by mutation of the enzymic nucleophile of a retaining glycosidase to a small non-nucleophilic residue. To date, five glycosynthases have been reported capable of synthesizing a range of β-glycosidic linkages. Methods to integrate protecting groups into glycosynthase-mediated glycosylations have been developed that broaden their applicability and enable finer control over product formation. Mutagenesis studies have improved the catalytic power of the original Abg glycosynthase, and a general methodology has been developed that allows the rapid screening of libraries of mutant glycosynthases for catalysts with improved activity. A method for determining aglycon substrate specificity has been developed to define the limits of substrate variation tolerated by a parent glycosidase and thence the derived glycosynthase. Together, these developments portend a bright future for the discovery of new glycosynthases and their widespread application as catalysts to assist in the rapid and efficient assembly of complex glycoconjugates.


Structure ◽  
2014 ◽  
Vol 22 (4) ◽  
pp. 590-601 ◽  
Author(s):  
Elisabeth Mohorko ◽  
Robin L. Owen ◽  
Goran Malojčić ◽  
Maurice S. Brozzo ◽  
Markus Aebi ◽  
...  

2003 ◽  
Vol 70 ◽  
pp. 39-52 ◽  
Author(s):  
Roy A. Black ◽  
John R. Doedens ◽  
Rajeev Mahimkar ◽  
Richard Johnson ◽  
Lin Guo ◽  
...  

Tumour necrosis factor α (TNFα)-converting enzyme (TACE/ADAM-17, where ADAM stands for a disintegrin and metalloproteinase) releases from the cell surface the extracellular domains of TNF and several other proteins. Previous studies have found that, while purified TACE preferentially cleaves peptides representing the processing sites in TNF and transforming growth factor α, the cellular enzyme nonetheless also sheds proteins with divergent cleavage sites very efficiently. More recent work, identifying the cleavage site in the p75 TNF receptor, quantifying the susceptibility of additional peptides to cleavage by TACE and identifying additional protein substrates, underlines the complexity of TACE-substrate interactions. In addition to substrate specificity, the mechanism underlying the increased rate of shedding caused by agents that activate cells remains poorly understood. Recent work in this area, utilizing a peptide substrate as a probe for cellular TACE activity, indicates that the intrinsic activity of the enzyme is somehow increased.


1978 ◽  
Vol 39 (03) ◽  
pp. 785-786 ◽  
Author(s):  
Y Legrand ◽  
J Caen ◽  
L Robert

2017 ◽  
Author(s):  
Kerstin Bathon ◽  
Isabel Weigand ◽  
Jens T Vanselow ◽  
Cristina L Ronchi ◽  
Dalmazi Guido Di ◽  
...  

2020 ◽  
Author(s):  
Carmanah D. Hunter ◽  
Elizabeth Porter ◽  
Christopher Cairo

This work investigated the substrate specificity of hNEU enzymes for a glycoprotein substrate (bovine submaxillary mucin) containing 9-<i>O</i>-acetylated and Neu5Gc residues. Using this model substrate, we observe a general trend for hNEU tolerance of Neu5Ac>Neu5Gc>>>Neu5,9Ac<sub>2</sub>, consistent with our previous results with glycolipid substrates. These results expand our understanding of hNEU enzyme specificity and suggest that naturally occurring modifications of sialic acids can play a role in regulating hNEU activity.


2019 ◽  
Author(s):  
Christian Zwick ◽  
Max Sosa ◽  
Hans Renata

We functionally characterize a nonheme dioxygenase from GE81112 biosynthesis and identify it as a citrulline hydroxylase. A bioinformatics guided engineering was performed to alter the substrate specificity of the enzyme.


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