Encompassing full nonmonotonicity within belief modification activity

1999 ◽  
Vol 3 (3) ◽  
pp. 131-140 ◽  
Author(s):  
P. Baroni
Keyword(s):  
Modification Activity

scholarly journals Plasmid R16 ArdA Protein Preferentially Targets Restriction Activity of the Type I Restriction-Modification System EcoKI

2003 ◽  
Vol 185 (6) ◽  
pp. 2022-2025 ◽  
Author(s):  
Angela T. Thomas ◽  
William J. Brammar ◽  
Brian M. Wilkins
Keyword(s):  
Type I ◽  
Bacterial Conjugation ◽  
Modification System ◽  
Restriction Modification System ◽  
Modification Activity ◽  
Restriction Modification

ABSTRACT The ArdA antirestriction protein of the IncB plasmid R16 selectively inhibited the restriction activity of EcoKI, leaving significant levels of modification activity under conditions in which restriction was almost completely prevented. The results are consistent with the hypothesis that ArdA functions in bacterial conjugation to allow an unmodified plasmid to evade restriction in the recipient bacterium and yet acquire cognate modification.

scholarly journals Box C/D guide RNAs recognize a maximum of 10 nt of substrates

2016 ◽  
Vol 113 (39) ◽  
pp. 10878-10883 ◽  
Author(s):  
Zuxiao Yang ◽  
Jinzhong Lin ◽  
Keqiong Ye
Keyword(s):  
Substrate Recognition ◽  
Active Conformation ◽  
Base Pairs ◽  
Recognition Mechanism ◽  
Site Specific ◽  
Guide Rnas ◽  
Modification Activity ◽  
Guide Sequence ◽  
Protein Channel ◽  
Insight Into

Box C/D RNAs guide site-specific 2′-O-methylation of RNAs in archaea and eukaryotes. The spacer regions between boxes C to D′ and boxes C′ to D contain the guide sequence that can form a stretch of base pairs with substrate RNAs. The lengths of spacer regions and guide-substrate duplexes are variable among C/D RNAs. In a previously determined structure of C/D ribonucleoprotein (RNP), a 12-nt-long spacer forms 10 bp with the substrate. How spacers and guide–substrate duplexes of other lengths are accommodated remains unknown. Here we analyze how the lengths of spacers and guide-substrate duplexes affect the modification activity and determine three structures of C/D RNPs assembled with different spacers and substrates. We show that the guide can only form a duplex of a maximum of 10 bp with the substrate during modification. Slightly shorter duplexes are tolerated, but longer duplexes must be unwound to fit into a capped protein channel for modification. Spacers with <12 nucleotides are defective, mainly because they cannot load the substrate in the active conformation. For spacers with >12 nucleotides, the excessive unpaired sequences near the box C/C′ side are looped out. Our results provide insight into the substrate recognition mechanism of C/D RNA and refute the RNA-swapped model for dimeric C/D RNP.

Mortgage Modification Activity—Recent Developments

2012 ◽  
Vol 21 (4) ◽  
pp. 55-68 ◽  
Author(s):  
Laurie S. Goodman ◽  
Roger Ashworth ◽  
Brian Landy ◽  
Lidan Yang
Keyword(s):  
Modification Activity ◽  
Recent Developments

scholarly journals Identification of a motif in Trm732 required for 2′-O-methylation of the tRNA anticodon loop by Trm7

2021 ◽  
Author(s):  
Holly M. Funk ◽  
Daisy J. DiVita ◽  
Hannah E. Sizemore ◽  
Kendal Wehrle ◽  
Catherine L. Weiner ◽  
...  
Keyword(s):  
Yeast Cells ◽  
Trna Modification ◽  
Anticodon Loop ◽  
Secondary Effects ◽  
Cellular Functions ◽  
Trna Modifications ◽  
Modification Activity ◽  
Human Disorders ◽  
Methylation Activity

Posttranscriptional tRNA modifications are essential for proper gene expression, and defects in the enzymes that perform tRNA modifications are associated with numerous human disorders. Throughout eukaryotes, 2′-O-methylation of residues 32 and 34 of the anticodon loop of tRNA is important for proper translation, and in humans, lack of these modifications results in non-syndromic X-linked intellectual disability. In yeast, the methyltransferase Trm7 forms a complex with Trm732 to 2′-O-methylate tRNA residue 32 and with Trm734 to 2′-O-methylate tRNA residue 34. Trm732 and Trm734 are required for the methylation activity of Trm7, but the role of these auxiliary proteins is not clear. Additionally, Trm732 and Trm734 homologs are implicated in biological processes not directly related to translation, suggesting that these proteins may have additional cellular functions. To identify critical amino acids in Trm732, we generated variants and tested their ability to function in yeast cells. We identified a conserved RRSAGLP motif in the conserved DUF2428 domain of Trm732 that is required for tRNA modification activity by both yeast Trm732 and its human homolog THADA. The identification of Trm732 variants that lack tRNA modification activity will help to determine if other biological functions ascribed to Trm732 and THADA are directly due to tRNA modification, or to secondary effects due to other functions of these proteins.

Cryochemical modification, activity, and toxicity of dioxidine

2017 ◽  
Vol 91 (2) ◽  
pp. 229-232 ◽  
Author(s):  
O. I. Vernaya ◽  
V. P. Shabatin ◽  
T. I. Shabatina ◽  
D. I. Khvatov ◽  
A. M. Semenov ◽  
...  
Keyword(s):  
Modification Activity ◽  
Cryochemical Modification
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