scholarly journals Improving upon Nature: Active Site Remodeling Produces Highly Efficient Aldolase Activity toward Hydrophobic Electrophilic Substrates

Biochemistry ◽  
2012 ◽  
Vol 51 (8) ◽  
pp. 1658-1668 ◽  
Author(s):  
Manoj Cheriyan ◽  
Eric J. Toone ◽  
Carol A. Fierke
Keyword(s):  
Active Site ◽  
Highly Efficient ◽  
Aldolase Activity

Active site engineering by surface sulfurization for a highly efficient oxygen evolution reaction: a case study of Co3O4 electrocatalysts

2018 ◽  
Vol 6 (45) ◽  
pp. 22497-22502 ◽  
Author(s):  
Ying Pan ◽  
Hangjuan Ren ◽  
Haiwei Du ◽  
Fuyang Cao ◽  
Yifeng Jiang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Oxygen Evolution ◽  
Active Site ◽  
Oxygen Evolution Reaction ◽  
Highly Efficient

Enhanced catalytic activity of Co3O4@CoSx through surface sulfurization.

Mutations Closer to the Active Site Improve the Promiscuous Aldolase Activity of 4-Oxalocrotonate Tautomerase More Effectively than Distant Mutations

ChemBioChem ◽  
2016 ◽  
Vol 17 (13) ◽  
pp. 1225-1228 ◽  
Author(s):  
Mehran Rahimi ◽  
Jan-Ytzen van der Meer ◽  
Edzard M. Geertsema ◽  
Harshwardhan Poddar ◽  
Bert-Jan Baas ◽  
...  
Keyword(s):  
Active Site ◽  
Aldolase Activity

Complete switch from α-2,3- to α-2,6-regioselectivity in Pasteurella dagmatis β-d-galactoside sialyltransferase by active-site redesign

2015 ◽  
Vol 51 (15) ◽  
pp. 3083-3086 ◽  
Author(s):  
Katharina Schmölzer ◽  
Tibor Czabany ◽  
Christiane Luley-Goedl ◽  
Tea Pavkov-Keller ◽  
Doris Ribitsch ◽  
...  
Keyword(s):  
Active Site ◽  
Highly Efficient

Incorporation of Pro7His and Met117Ala substitutions resulted in a completely regioselective and highly efficient α-2,6-sialyltransferase.

scholarly journals 6-Pyruvoyltetrahydropterin Synthase Paralogs Replace the Folate Synthesis Enzyme Dihydroneopterin Aldolase in Diverse Bacteria

2009 ◽  
Vol 191 (13) ◽  
pp. 4158-4165 ◽  
Author(s):  
Anne Pribat ◽  
Linda Jeanguenin ◽  
Aurora Lara-Núñez ◽  
Michael J. Ziemak ◽  
John E. Hyde ◽  
...  
Keyword(s):  
Active Site ◽  
Genes Encoding ◽  
Folate Biosynthesis ◽  
Catalytic Cysteine ◽  
Aldolase Activity ◽  
Bacterial Genes ◽  
Almost All ◽  
Dihydroneopterin Aldolase

ABSTRACT Dihydroneopterin aldolase (FolB) catalyzes conversion of dihydroneopterin to 6-hydroxymethyldihydropterin (HMDHP) in the classical folate biosynthesis pathway. However, folB genes are missing from the genomes of certain bacteria from the phyla Chloroflexi, Acidobacteria, Firmicutes, Planctomycetes, and Spirochaetes. Almost all of these folB-deficient genomes contain an unusual paralog of the tetrahydrobiopterin synthesis enzyme 6-pyruvoyltetrahydropterin synthase (PTPS) in which a glutamate residue replaces or accompanies the catalytic cysteine. A similar PTPS paralog from the malaria parasite Plasmodium falciparum is known to form HMDHP from dihydroneopterin triphosphate in vitro and has been proposed to provide a bypass to the FolB step in vivo. Bacterial genes encoding PTPS-like proteins with active-site glutamate, cysteine, or both residues were accordingly tested together with the P. falciparum gene for complementation of the Escherichia coli folB mutation. The P. falciparum sequence and bacterial sequences with glutamate or glutamate plus cysteine were active; those with cysteine alone were not. These results demonstrate that PTPS paralogs with an active-site glutamate (designated PTPS-III proteins) can functionally replace FolB in vivo. Recombinant bacterial PTPS-III proteins, like the P. falciparum enzyme, mediated conversion of dihydroneopterin triphosphate to HMDHP, but other PTPS proteins did not. Neither PTPS-III nor other PTPS proteins exhibited significant dihydroneopterin aldolase activity. Phylogenetic analysis indicated that PTPS-III proteins may have arisen independently in various PTPS lineages. Consistent with this possibility, merely introducing a glutamate residue into the active site of a PTPS protein conferred incipient activity in the growth complementation assay, and replacing glutamate with alanine in a PTPS-III protein abolished complementation.

scholarly journals Enhancing Methane Conversion by Modification of Zn States in Co-Reaction of MTA

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1540
Author(s):  
Yue Yu ◽  
Zhixiang Xi ◽  
Bingjie Zhou ◽  
Binbo Jiang ◽  
Zuwei Liao ◽  
...  
Keyword(s):  
Active Site ◽  
Methane Conversion ◽  
Strong Acid ◽  
Acid Sites ◽  
Methane Activation ◽  
Reaction Conditions ◽  
Holy Grail ◽  
Highly Efficient ◽  
Strong Acid Sites ◽  
Capacity Loading

Limited by harsh reaction conditions, the activation and utilization of methane were regarded as holy grail reaction. Co-reaction with methanol, successfully realizing mild conversion below 450 °C, provides practical strategies for methane conversion on metal-loaded ZSM-5 zeolites, especially for highly efficient Zn loaded ones. However, Zn species, regarded as active acid sites on the zeolite, have not been sufficiently studied. In this paper, Zn-loaded ZSM-5 zeolite was prepared, and Zn was modified by capacity, loading strategy, and treating atmosphere. Apparent methane conversion achieves 15.3% for 1.0Zn/Z-H2 (16.8% as calculated net conversion) with a significantly reduced loading of 1.0 wt.% against deactivation, which is among the best within related zeolite materials. Besides, compared to the MTA reaction, the addition of methane promotes the high-valued aromatic production from 49.4% to 54.8%, and inhibits the C10+ production from 7.8% to 3.6%. Notably, Zn2+ is found to be another active site different from the reported ZnOH+. Medium strong acid sites are proved to be beneficial for methane activation. This work provides suggestions for the modification of the Zn active site, in order to prepare highly efficient catalysts for methane activation and BTX production in co-reaction with methanol.

In situ nanoarchitecturing and active-site engineering toward highly efficient carbonaceous electrocatalysts

Nano Energy ◽  
2019 ◽  
Vol 59 ◽  
pp. 207-215 ◽  
Author(s):  
Kai Yuan ◽  
Chenbao Lu ◽  
Stavroula Sfaelou ◽  
Xiaxia Liao ◽  
Xiaodong Zhuang ◽  
...  
Keyword(s):  
Active Site ◽  
Highly Efficient

scholarly journals Aldolase A Ins(1,4,5)P3-binding domains as determined by site-directed mutagenesis

1999 ◽  
Vol 341 (3) ◽  
pp. 805-812 ◽  
Author(s):  
Carl B. BARON ◽  
Dean R. TOLAN ◽  
Kyung H. CHOI ◽  
Ronald F. COBURN
Keyword(s):  
Catalytic Activity ◽  
Active Site ◽  
Electrostatic Interactions ◽  
Bond Cleavage ◽  
Site Directed Mutagenesis ◽  
Binding Domains ◽  
Carbon Carbon Bond ◽  
Catalytically Active ◽  
Aldolase Activity ◽  
Aldolase A

We substituted neutral amino acids for some positively charged residues (R42, K107, K146, R148 and K229) that line the active site of aldolase A in an effort to determine binding sites for inositol 1,4,5-trisphosphate. In addition, D33 (involved in carbon-carbon bond cleavage) was mutated. K229A and D33S aldolases showed almost no catalytic activity, but Ins(1,4,5)P3 binding was similar to that determined with the use of wild-type aldolase A. R42A, K107A, K146R and R148A had markedly decreased affinities for Ins(1,4,5)P3 binding, increased EC50 values for Fru(1,6)P2-evoked release of bound Ins(1,4,5)P3 and increased Ki values for Ins(1,4,5)P3-evoked inhibition of aldolase activity. K146Q (positive charge removal) had essentially no catalytic activity and could not bind Ins(1,4,5)P3. Computer-simulated docking of Ins(1,4,5)P3 in the aldolase A structure was consistent with electrostatic binding of Ins(1,4,5)P3 to K107, K146, R148, R42, R303 and backbone nitrogens, as has been reported for Fru(1,6)P2 binding. Results indicate that Ins(1,4,5)P3 binding occurs at the active site and is not dependent on having a catalytically active enzyme; they also suggest that there is competition between Ins(1,4,5)P3 and Fru(1,6)P2 for binding. Although Ins(1,4,5)P3 binding to aldolase involved electrostatic interactions, the aldolase A Ins(1,4,5)P3-binding domain did not show other similarities to pleckstrin homology domains or phosphotyrosine-binding domains known to bind Ins(1,4,5)P3 in other proteins.

scholarly journals Electrochemical control of [FeFe]-hydrogenase single crystals reveals complex redox populations at the catalytic site

2021 ◽  
Author(s):  
Simone Morra ◽  
Jifu Duan ◽  
Martin Winkler ◽  
Philip A Ash ◽  
Thomas Happe ◽  
...  
Keyword(s):  
Single Crystals ◽  
Active Site ◽  
Catalytic Site ◽  
Highly Efficient ◽  
Electrochemical Control

Elucidating the distribution of intermediates at the active site of redox metalloenzymes is vital to understanding their highly efficient catalysis. Here we demonstrate that it is possible to generate, and...

scholarly journals A Unique Ru-N4-P Coordinated Structure Synergistically Waking Up the Nonmetal P Active Site for Hydrogen Production

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Chuanqiang Wu ◽  
Shiqing Ding ◽  
Daobin Liu ◽  
Dongdong Li ◽  
Shuangming Chen ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Active Site ◽  
Active Sites ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Highly Efficient ◽  
Catalytic Sites ◽  
Catalytically Active ◽  
Doped Graphene ◽  
Waking Up

Numerous experiments have demonstrated that the metal atom is the active center of monoatomic catalysts for hydrogen evolution reaction (HER), while the active sites of nonmetal doped atoms are often neglected. By combining theoretical prediction and experimental verification, we designed a unique ternary Ru-N4-P coordination structure constructed by monodispersed Ru atoms supported on N,P dual-doped graphene for highly efficient hydrogen evolution in acid solution. The density functional theory calculations indicate that the charge polarization will lead to the most charge accumulation at P atoms, which results in a distinct nonmetallic P active sites with the moderate H∗ adsorption energy. Notably, these P atoms mainly supply highly efficient catalytic sites with ultrasmall absorption energy of 0.007 eV. Correspondingly, the Ru-N4-P demonstrated outstanding HER performance not only in an acidic condition but also in alkaline environment. Notably, the performance of Ru-NPC catalyst at high current is even superior to the commercial Pt/C catalysts, whether in acidic or alkaline medium. Our in situ synchrotron radiation infrared spectra demonstrate that a P-Hads intermediate is continually emerging on the Ru-NPC catalyst, actively proving the nonmetallic P catalytically active site in HER that is very different with previously reported metallic sites.

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