scholarly journals Comparative Analysis of the Conversion of Mandelonitrile and 2-Phenylpropionitrile by a Large Set of Variants Generated from a Nitrilase Originating from Pseudomonas fluorescens EBC191

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4232 ◽  
Author(s):  
Stolz ◽  
Eppinger ◽  
Sosedov ◽  
Kiziak
Keyword(s):  
Pseudomonas Fluorescens ◽  
Mandelic Acid ◽  
Single Point ◽  
Enantiomeric Excess ◽  
Point Mutations ◽  
General Information ◽  
Large Set ◽  
Single Point Mutations ◽  
Aliphatic Nitriles ◽  
Relationship Of

The arylacetonitrilase from the bacterium Pseudomonas fluorescens EBC191 has been intensively studied as a model to understand the molecular basis for the substrate-, reaction-, and enantioselectivity of nitrilases. The nitrilase converts various aromatic and aliphatic nitriles to the corresponding acids and varying amounts of the corresponding amides. The enzyme has been analysed by site-specific mutagenesis and more than 50 different variants have been generated and analysed for the conversion of (R,S)-mandelonitrile and (R,S)-2-phenylpropionitrile. These comparative analyses demonstrated that single point mutations are sufficient to generate enzyme variants which hydrolyse (R,S)-mandelonitrile to (R)-mandelic acid with an enantiomeric excess (ee) of 91% or to (S)-mandelic acid with an ee-value of 47%. The conversion of (R,S)-2-phenylpropionitrile by different nitrilase variants resulted in the formation of either (S)- or (R)-2-phenylpropionic acid with ee-values up to about 80%. Furthermore, the amounts of amides that are produced from (R,S)-mandelonitrile and (R,S)-2-phenylpropionitrile could be changed by single point mutations between 2%–94% and <0.2%–73%, respectively. The present study attempted to collect and compare the results obtained during our previous work, and to obtain additional general information about the relationship of the amide forming capacity of nitrilases and the enantiomeric composition of the products.

scholarly journals Hypertrophic cardiomyopathy disease results from disparate impairments of cardiac myosin function and auto-inhibition

2018 ◽  
Author(s):  
Julien Robert-Paganin ◽  
Daniel Auguin ◽  
Anne Houdusse
Keyword(s):  
Single Point ◽  
Point Mutations ◽  
Clear Understanding ◽  
Large Set ◽  
Cardiac Myosin ◽  
Sarcomeric Proteins ◽  
X Ray Crystallography ◽  
Lever Arm ◽  
Mechanical Compliance ◽  
Single Point Mutations

Abstract:Hypertrophic cardiomyopathies (HCM) result from distinct single-point mutations in sarcomeric proteins that lead to muscle hypercontractility. While different models account for a pathological increase in the power output, clear understanding of the molecular basis of dysfunction in HCM is the mandatory next step to improve current treatments. An optimized quasi-atomic model of the sequestered state of cardiac myosin coupled to X-ray crystallography and in silico analysis of the mechanical compliance of the lever arm allowed us to perform a systematic study for a large set of HCM mutations. We define different classes of mutations depending on their effects on lever arm compliance, sequestered state stability and motor functions. This work reconciles previous models and explains how distinct HCM mutations can have disparate effects on the motor mechano-chemical parameters and yet lead to the same disease. The framework presented here can guide future investigations aiming at finding HCM treatments.

Cupin Variants as Macromolecular Ligand Library for Stereoselective Michael Addition of Nitroalkanes

2019 ◽  
Author(s):  
Nobutaka Fujieda ◽  
Miho Yuasa ◽  
Yosuke Nishikawa ◽  
Genji Kurisu ◽  
Shinobu Itoh ◽  
...  
Keyword(s):  
Michael Addition ◽  
In Silico ◽  
Addition Reaction ◽  
Single Point ◽  
Point Mutations ◽  
Unsaturated Ketone ◽  
Michael Addition Reaction ◽  
Beta Barrel ◽  
Cupin Superfamily ◽  
Single Point Mutations

Cupin superfamily proteins (TM1459) work as a macromolecular ligand framework with a double-stranded beta-barrel structure ligating to a Cu ion through histidine side chains. Variegating the first coordination sphere of TM1459 revealed that H52A and H54A/H58A mutants effectively catalyzed the diastereo- and enantio-selective Michael addition reaction of nitroalkanes to an α,β-unsaturated ketone. Moreover, in silico substrate docking signified C106N and F104W single-point mutations, which inverted the diastereoselectivity of H52A and further improved the stereoselectivity of H54A/H58A, respectively.

Single-Point Mutations in Qβ Virus-like Particles Change Binding to Cells

2021 ◽  
Author(s):  
Marisa L. Martino ◽  
Stephen N. Crooke ◽  
Marianne Manchester ◽  
M.G. Finn
Keyword(s):  
Single Point ◽  
Point Mutations ◽  
Virus Like Particles ◽  
Single Point Mutations

MinD directly interacting with FtsZ at the H10 helix suggests a model for robust activation of MinC to destabilize FtsZ polymers

2017 ◽  
Vol 474 (18) ◽  
pp. 3189-3205 ◽  
Author(s):  
Ashoka Chary Taviti ◽  
Tushar Kant Beuria
Keyword(s):  
Cell Division ◽  
Single Point ◽  
Point Mutations ◽  
Direct Interaction ◽  
Ring Formation ◽  
Z Ring ◽  
Single Point Mutations ◽  
Biochemical Analyses ◽  
Ftsz Assembly ◽  
The Mind

Cell division in bacteria is a highly controlled and regulated process. FtsZ, a bacterial cytoskeletal protein, forms a ring-like structure known as the Z-ring and recruits more than a dozen other cell division proteins. The Min system oscillates between the poles and inhibits the Z-ring formation at the poles by perturbing FtsZ assembly. This leads to an increase in the FtsZ concentration at the mid-cell and helps in Z-ring positioning. MinC, the effector protein, interferes with Z-ring formation through two different mechanisms mediated by its two domains with the help of MinD. However, the mechanism by which MinD triggers MinC activity is not yet known. We showed that MinD directly interacts with FtsZ with an affinity stronger than the reported MinC–FtsZ interaction. We determined the MinD-binding site of FtsZ using computational, mutational and biochemical analyses. Our study showed that MinD binds to the H10 helix of FtsZ. Single-point mutations at the charged residues in the H10 helix resulted in a decrease in the FtsZ affinity towards MinD. Based on our findings, we propose a novel model for MinCD–FtsZ interaction, where MinD through its direct interaction with FtsZ would trigger MinC activity to inhibit FtsZ functions.

scholarly journals Single-point mutations of hepatitis C virus NS3 that impair p53 interaction and anti-apoptotic activity of NS3

2006 ◽  
Vol 340 (3) ◽  
pp. 792-799 ◽  
Author(s):  
Motofumi Tanaka ◽  
Motoko Nagano-Fujii ◽  
Lin Deng ◽  
Satoshi Ishido ◽  
Kiyonao Sada ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Single Point ◽  
Point Mutations ◽  
Single Point Mutations ◽  
Apoptotic Activity

scholarly journals Genetic diversity of the Neotropical otter (Lontra longicaudis Olfers, 1818) in Southern and Southeastern Brazil

2007 ◽  
Vol 67 (4 suppl) ◽  
pp. 813-818 ◽  
Author(s):  
CS. Trinca ◽  
HF. Waldemarin ◽  
E. Eizirik
Keyword(s):  
Molecular Diversity ◽  
Single Point ◽  
Haplotype Diversity ◽  
Point Mutations ◽  
Conservation Strategies ◽  
Southeastern Brazil ◽  
Nucleotide Variability ◽  
Single Point Mutations ◽  
High Level ◽  
Lontra Longicaudis

The Neotropical otter is one of the least known otter species, and it is considered to be threatened to various degrees throughout its geographic range. Little information exists on the ecological characteristics of this species, and no genetic study has been published about it until now, hampering the design of adequate conservation strategies for its populations. To contribute with genetic information to comprehensive conservation efforts on behalf of L. longicaudis, we characterized the molecular diversity of the 5’ portion of the mtDNA control region in samples from this species collected in Southern and Southeastern Brazil. The sequence analysis revealed a high level of haplotype diversity (h = 0.819; SE = 0.0052) and nucleotide variability ranging from 0.0039 to 0.0067. One of the sampled haplotypes was the most common in both regions and, from this sequence, several other (locally occurring) haplotypes could be derived by single point mutations. No significant genetic differentiation was observed between the Southern and Southeastern regions.

scholarly journals Changing the Antigen Binding Specificity by Single Point Mutations of an Anti-p24 (HIV-1) Antibody

2000 ◽  
Vol 165 (8) ◽  
pp. 4505-4514 ◽  
Author(s):  
Karsten Winkler ◽  
Achim Kramer ◽  
Gabriele Küttner ◽  
Martina Seifert ◽  
Christa Scholz ◽  
...  
Keyword(s):  
Single Point ◽  
Point Mutations ◽  
Binding Specificity ◽  
Antigen Binding ◽  
Single Point Mutations ◽  
Hiv 1
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