Trichodiene synthase. Synergistic inhibition by inorganic pyrophosphate and aza analogs of the bisabolyl cation.

1992 ◽  
Vol 57 (12) ◽  
pp. 3454-3462 ◽  
Author(s):  
David E. Cane ◽  
Guohan Yang ◽  
Robert M. Coates ◽  
Hyung Jung Pyun ◽  
Thomas M. Hohn
Keyword(s):  
Inorganic Pyrophosphate ◽  
Synergistic Inhibition ◽  
Trichodiene Synthase

Crystal structures of plant inorganic pyrophosphatase, an enzyme with a moonlighting autoproteolytic activity

2019 ◽  
Vol 476 (16) ◽  
pp. 2297-2319 ◽  
Author(s):  
Marta Grzechowiak ◽  
Milosz Ruszkowski ◽  
Joanna Sliwiak ◽  
Kamil Szpotkowski ◽  
Michal Sikorski ◽  
...  
Keyword(s):  
Site Directed Mutagenesis ◽  
Size Exclusion ◽  
Inorganic Pyrophosphatase ◽  
Prolonged Storage ◽  
Mitochondrial Targeting ◽  
Cleavage Rate ◽  
Inorganic Pyrophosphate ◽  
Putative Signal Peptide ◽  
Targeting Peptide

Abstract Inorganic pyrophosphatases (PPases, EC 3.6.1.1), which hydrolyze inorganic pyrophosphate to phosphate in the presence of divalent metal cations, play a key role in maintaining phosphorus homeostasis in cells. DNA coding inorganic pyrophosphatases from Arabidopsis thaliana (AtPPA1) and Medicago truncatula (MtPPA1) were cloned into a bacterial expression vector and the proteins were produced in Escherichia coli cells and crystallized. In terms of their subunit fold, AtPPA1 and MtPPA1 are reminiscent of other members of Family I soluble pyrophosphatases from bacteria and yeast. Like their bacterial orthologs, both plant PPases form hexamers, as confirmed in solution by multi-angle light scattering and size-exclusion chromatography. This is in contrast with the fungal counterparts, which are dimeric. Unexpectedly, the crystallized AtPPA1 and MtPPA1 proteins lack ∼30 amino acid residues at their N-termini, as independently confirmed by chemical sequencing. In vitro, self-cleavage of the recombinant proteins is observed after prolonged storage or during crystallization. The cleaved fragment corresponds to a putative signal peptide of mitochondrial targeting, with a predicted cleavage site at Val31–Ala32. Site-directed mutagenesis shows that mutations of the key active site Asp residues dramatically reduce the cleavage rate, which suggests a moonlighting proteolytic activity. Moreover, the discovery of autoproteolytic cleavage of a mitochondrial targeting peptide would change our perception of this signaling process.

scholarly journals Enhanced anti-melanoma efficacy through a combination of the armed oncolytic adenovirus ZD55-IL-24 and immune checkpoint blockade in B16-bearing immunocompetent mouse model

2021 ◽  
Author(s):  
Hai-Jun Hu ◽  
Xiu Liang ◽  
Hai-Lang Li ◽  
Huai-Yuan Wang ◽  
Jin-Fa Gu ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Mouse Model ◽  
Immune Checkpoint Blockade ◽  
Oncolytic Adenovirus ◽  
Immunocompetent Mouse ◽  
Combination Strategy ◽  
Obvious Effect ◽  
Immune Infiltration ◽  
Synergistic Inhibition ◽  
Recent Treatment

AbstractAlthough the recent treatment in melanoma through the use of anti-PD-1 immunotherapy is successful, the efficacy of this approach remains to be improved. Here, we explore the feasibility of combination strategy with the armed oncolytic adenovirus ZD55-IL-24 and PD-1 blockade. We find that combination therapy with localized ZD55-IL-24 and systemic PD-1 blockade leads to synergistic inhibition of both local and distant established tumors in B16-bearing immunocompetent mouse model. Our further mechanism investigation reveals that synergistic therapeutic effect is associated with marked promotion of tumor immune infiltration and recognition in both local and distant tumors as well as spleens. PD-1 blockade has no obvious effect on promotion of tumor immune infiltration and recognition. Localized therapy with ZD55-IL-24, however, can help PD-1 blockade to overcome the limitation of relatively low tumor immune infiltration and recognition. This study provides a rationale for investigation of such combination therapy in the clinic.

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