scholarly journals Formation of the Unusual Semivolatile Diterpene Rhizathalene by the Arabidopsis Class I Terpene Synthase TPS08 in the Root Stele Is Involved in Defense against Belowground Herbivory

2013 ◽  
Vol 25 (3) ◽  
pp. 1108-1125 ◽  
Author(s):  
Martha M. Vaughan ◽  
Qiang Wang ◽  
Francis X. Webster ◽  
Dave Kiemle ◽  
Young J. Hong ◽  
...  
Keyword(s):  
Class I ◽  
Terpene Synthase ◽  
Belowground Herbivory ◽  
Root Stele

An alternative splicing alters the product outcome of a class I terpene synthase in Isodon rubescens

2019 ◽  
Vol 512 (2) ◽  
pp. 310-313 ◽  
Author(s):  
Baolong Jin ◽  
Juan Guo ◽  
Jinfu Tang ◽  
Yuru Tong ◽  
Ying Ma ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Class I ◽  
Terpene Synthase ◽  
Product Outcome

scholarly journals Identification of amino acid networks governing catalysis in the closed complex of class I terpene synthases

2016 ◽  
Vol 113 (8) ◽  
pp. E958-E967 ◽  
Author(s):  
Patrick Schrepfer ◽  
Alexander Buettner ◽  
Christian Goerner ◽  
Michael Hertel ◽  
Jeaphianne van Rijn ◽  
...  
Keyword(s):  
Active Site ◽  
In Silico ◽  
Class I ◽  
Terpene Synthase ◽  
Terpene Synthases ◽  
Substrate Analogs ◽  
Inactive Form ◽  
In Silico Modeling ◽  
Site Localization ◽  
Reaction Cascades

Class I terpene synthases generate the structural core of bioactive terpenoids. Deciphering structure–function relationships in the reactive closed complex and targeted engineering is hampered by highly dynamic carbocation rearrangements during catalysis. Available crystal structures, however, represent the open, catalytically inactive form or harbor nonproductive substrate analogs. Here, we present a catalytically relevant, closed conformation of taxadiene synthase (TXS), the model class I terpene synthase, which simulates the initial catalytic time point. In silico modeling of subsequent catalytic steps allowed unprecedented insights into the dynamic reaction cascades and promiscuity mechanisms of class I terpene synthases. This generally applicable methodology enables the active-site localization of carbocations and demonstrates the presence of an active-site base motif and its dominating role during catalysis. It additionally allowed in silico-designed targeted protein engineering that unlocked the path to alternate monocyclic and bicyclic synthons representing the basis of a myriad of bioactive terpenoids.

Electron microscopy analysis of degenerating pancreatic ß cells in transgenic mice expressing the MHC Class I antigen Dd

1990 ◽  
Vol 48 (3) ◽  
pp. 548-549
Author(s):  
T. A. Stewart ◽  
D. Liggitt ◽  
S. Pitts ◽  
L. Martin ◽  
M. Siegel ◽  
...  
Keyword(s):  
Type I Diabetes ◽  
Disease Process ◽  
Class Ii ◽  
Class I ◽  
Type I ◽  
Aberrant Expression ◽  
Mhc Molecules ◽  
Endogenous Insulin ◽  
Class Ii Mhc ◽  
Ifn Γ

Insulin-dependant (Type I) diabetes mellitus (IDDM) is a metabolic disorder resulting from the lack of endogenous insulin secretion. The disease is thought to result from the autoimmune mediated destruction of the insulin producing ß cells within the islets of Langerhans. The disease process is probably triggered by environmental agents, e.g. virus or chemical toxins on a background of genetic susceptibility associated with particular alleles within the major histocompatiblity complex (MHC). The relation between IDDM and the MHC locus has been reinforced by the demonstration of both class I and class II MHC proteins on the surface of ß cells from newly diagnosed patients as well as mounting evidence that IDDM has an autoimmune pathogenesis. In 1984, a series of observations were used to advance a hypothesis, in which it was suggested that aberrant expression of class II MHC molecules, perhaps induced by gamma-interferon (IFN γ) could present self antigens and initiate an autoimmune disease. We have tested some aspects of this model and demonstrated that expression of IFN γ by pancreatic ß cells can initiate an inflammatory destruction of both the islets and pancreas and does lead to IDDM.

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