scholarly journals A novel decrystallizing protein CxEXL22 from Arthrobotrys sp. CX1 capable of synergistically hydrolyzing cellulose with cellulases

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Rong Li ◽  
Yunze Sun ◽  
Yihao Zhou ◽  
Jiawei Gai ◽  
Linlu You ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Hydrophobic Surface ◽  
Crystalline Cellulose ◽  
Crystalline Region ◽  
Strong Activity ◽  
Hydrophobic Residues ◽  
Cellulose Accessibility ◽  
Hydrolysis Of ◽  
Β Sheet

AbstractA novel expansin-like protein (CxEXL22) has been identified and characterized from newly isolated Arthrobotrys sp. CX1 that can cause cellulose decrystallization. Unlike previously reported expansin-like proteins from microbes, CxEXL22 has a parallel β-sheet domain at the N terminal, containing many hydrophobic residues to form the hydrophobic surface as part of the groove. The direct phylogenetic relationship implied the genetic transfers occurred from nematode to nematicidal fungal Arthrobotrys sp. CX1. CxEXL22 showed strong activity for the hydrolysis of hydrogen bonds between cellulose molecules, especially when highly crystalline cellulose was used as substrate. The hydrolysis efficiency of Avicel was increased 7.9-fold after pretreating with CxEXL22. The rupture characterization of crystalline region indicated that CxEXL22 strongly binds cellulose and breaks up hydrogen bonds in the crystalline regions of cellulose to split cellulose chains, causing significant depolymerization to expose much more microfibrils and enhances cellulose accessibility.

Characterization of cellulose and TEMPO-oxidized celluloses prepared from Eucalyptus globulus

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yuko Ono ◽  
Miyuki Takeuchi ◽  
Yaxin Zhou ◽  
Akira Isogai
Keyword(s):  
Eucalyptus Globulus ◽  
Dry Weight ◽  
Cellulose Microfibrils ◽  
Crystalline Cellulose ◽  
Crystalline Region ◽  
Cellulose I ◽  
Nmr Spectrum ◽  
Significant Damage ◽  
Mediated Oxidation

Abstract Eucalyptus (Eucalyptus globulus) cellulose was isolated from wood powder by dewaxing, delignification, and subsequent 4% NaOH extraction. 2,2,6,6-Tetramethyl-piperidine-1-oxyl (TEMPO)-oxidized eucalyptus celluloses were prepared from never-dried eucalyptus cellulose (EC) in yields of 96% and 72% (based on the dry weight of EC) when oxidized with NaOCl of 5 and 10 mmol/g-EC, respectively. Their carboxy contents were 1.4 and 1.8 mmol/g, respectively, when determined by conductivity titration. The crystallinity of cellulose I for EC decreased by TEMPO-mediated oxidation, showing that the originally crystalline region in EC was partly converted to disordered regions by TEMPO-mediated oxidation. Correspondingly, the relative signal area of C6‒OH/C1 with the trans-gauche (tg) conformation attributed to crystalline cellulose I in the solid-state 13C NMR spectrum of EC decreased from 0.42 to 0.34 by TEMPO-mediated oxidation with NaOCl of 10 mmol/g-EC. TEMPO-oxidized EC prepared with NaOCl of 10 mmol/g-EC was almost completely converted into individual TEMPO-oxidized EC nanofibrils (TEMPO-ECNFs) of homogeneous widths of ∼3 nm widths and lengths of >1 μm by mechanical disintegration in water. However, the TEMPO-ECNFs contained many kinks and had uneven surfaces, probably owing to significant damage occurring on the surface cellulose molecules of crystalline cellulose microfibrils during TEMPO-mediated oxidation.

scholarly journals Characterization of Hidden Chirality: Two-Fold Helicity in β-Strands

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 499 ◽  
Author(s):  
Toshiyuki Sasaki ◽  
Mikiji Miyata
Keyword(s):  
Hydrogen Bonds ◽  
Polypeptide Chain ◽  
Structural Motif ◽  
High Dimensional ◽  
Point Approximation ◽  
Β Sheets ◽  
Α Helix ◽  
Β Sheet

A β-strand is a component of a β-sheet and is an important structural motif in biomolecules. An α-helix has clear helicity, while chirality of a β-strand had been discussed on the basis of molecular twists generated by forming hydrogen bonds in parallel or non-parallel β-sheets. Herein we describe handedness determination of two-fold helicity in a zig-zag β-strand structure. Left- (M) and right-handedness (P) of the two-fold helicity was defined by application of two concepts: tilt-chirality and multi-point approximation. We call the two-fold helicity in a β-strand, whose handedness has been unrecognized and unclarified, as hidden chirality. Such hidden chirality enables us to clarify precise chiral characteristics of biopolymers. It is also noteworthy that characterization of chirality of high dimensional structures like a β-strand and α-helix, referred to as high dimensional chirality (HDC) in the present study, will contribute to elucidation of the possible origins of chirality and homochirality in nature because such HDC originates from not only asymmetric centers but also conformations in a polypeptide chain.

scholarly journals Synthesis and structural characterization of four dichloridobis(cyclopropylalkynylamidine)metal complexes

2018 ◽  
Vol 74 (11) ◽  
pp. 1658-1664
Author(s):  
Sida Wang ◽  
Phil Liebing ◽  
Felix Engelhardt ◽  
Liane Hilfert ◽  
Sabine Busse ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Triple Bond ◽  
Spectroscopic Data ◽  
Central Metal Atom ◽  
Central Metal ◽  
Elemental Analyses ◽  
Hydrolysis Of ◽  
Cl Atoms

Deliberate hydrolysis of lithium cyclopropylalkynylamidinates, Li[c-C3H5—C[triple-bond]C(NR′)2] [R′ = i Pr, Cy = cyclohexyl)], afforded the hitherto unknown neutral cyclopropylalkynylamidine derivatives c-C3H5—C[triple-bond]C—C(NR′)(NHR′) [R′ = i Pr (1), Cy (2)]. Subsequent reactions of 1 or 2 with metal(II) chlorides, MCl2 (M = Mn, Fe, Co), provided the title complexes dichloridobis(3-cyclopropyl-N,N′-diisopropylprop-2-ynamidine)manganese(II), [MnCl2(C12H20N2)2], (3), dichloridobis(3-cyclopropyl-N,N′-diisopropylprop-2-ynamidine)iron(II), [FeCl2(C12H20N2)2], (4), dichloridobis(N,N′-dicyclohexyl-3-cyclopropylprop-2-ynamidine)iron(II), [FeCl2(C18H28N2)2], (5), and dichloridobis(N,N′-dicyclohexyl-3-cyclopropylprop-2-ynamidine)cobalt(II), [CoCl2(C18H28N2)2], (6), or more generally MCl2[c-C3H5—C[triple-bond]C—C(NR′)(NHR′)]2 [R′ = i Pr, M = Mn (3), Fe (4); R′ = Cy, M = Fe (5), Co (6)] in moderate yields (30–39%). Besides their spectroscopic data (IR and MS) and elemental analyses, all complexes 3–6 were structurally characterized. The two isopropyl-substituted complexes 3 and 4 are isotypic, and so are the cyclohexyl-substituted complexes 5 and 6. In all cases, the central metal atom is coordinated by two Cl atoms and two N atoms in a distorted-tetrahedral fashion, and the structure is supported by intramolecular N—H...Cl hydrogen bonds.

scholarly journals Characterization of a C—C Bond Hydrolase from Sphingomonas wittichii RW1 with Novel Specificities towards Polychlorinated Biphenyl Metabolites

2007 ◽  
Vol 189 (11) ◽  
pp. 4038-4045 ◽  
Author(s):  
Stephen Y. K. Seah ◽  
Jiyuan Ke ◽  
Geoffroy Denis ◽  
Geoff P. Horsman ◽  
Pascal D. Fortin ◽  
...  
Keyword(s):  
Polychlorinated Biphenyl ◽  
Phylogenetic Analyses ◽  
Inverse Pcr ◽  
Gene Encoding ◽  
Hydrophobic Residues ◽  
Burkholderia Xenovorans ◽  
Lower Specificity ◽  
Sphingomonas Wittichii ◽  
Hydrolysis Of

ABSTRACT Sphingomonas wittichii RW1 degrades chlorinated dibenzofurans and dibenzo-p-dioxins via meta cleavage. We used inverse PCR to amplify dxnB2, a gene encoding one of three meta-cleavage product (MCP) hydrolases identified in the organism that are homologues of BphD involved in biphenyl catabolism. Purified DxnB2 catalyzed the hydrolysis of 8-OH 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate (HOPDA) approximately six times faster than for HOPDA at saturating substrate concentrations. Moreover, the specificity of DxnB2 for HOPDA (k cat/Km = 1.2 × 107 M−1 s−1) was about half that of the BphDs of Burkholderia xenovorans LB400 and Rhodococcus globerulus P6, two potent polychlorinated biphenyl (PCB)-degrading strains. Interestingly, DxnB2 transformed 3-Cl and 4-OH HOPDAs, compounds that inhibit the BphDs and limit PCB degradation. DxnB2 had a higher specificity for 9-Cl HOPDA than for HOPDA but a lower specificity for 8-Cl HOPDA (k cat/Km = 1.7 × 106 M−1 s−1), the chlorinated analog of 8-OH HOPDA produced during dibenzofuran catabolism. Phylogenetic analyses based on structure-guided sequence alignment revealed that DxnB2 belongs to a previously unrecognized class of MCP hydrolases, evolutionarily divergent from the BphDs although the physiological substrates of both enzyme types are HOPDAs. However, both classes of enzymes have mainly small hydrophobic residues lining the subsite that binds the C-6 phenyl of HOPDA, in contrast to the bulky hydrophobic residues (Phe106, Phe135, Trp150, and Phe197) found in the class II enzymes that prefer substrates possessing a C-6 alkyl. Thr196 and/or Asn203 appears to be an important determinant of specificity for DxnB2, potentially forming hydrogen bonds with the 8-OH substituent. This study demonstrates that the substrate specificities of evolutionarily divergent hydrolases may be useful for degrading mixtures of pollutants, such as PCBs.

Preparation and characterization of diethylnicotinamidium perchlorate

2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Iveta Ondrejkovičová ◽  
Dušan Mikloš ◽  
Silvia Štefániková
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Ir Spectra ◽  
Title Compound ◽  
Linear Chain ◽  
Ionic Interactions ◽  
X Ray ◽  
Hydrolysis Of ◽  
Infinite Linear

AbstractThe title compound is the first example of N,N′-diethylnicotinamidium, [denaH]+, salt which has been characterized by X-ray analysis and IR spectra. [denaH]ClO4 was obtained from the reaction mixture prepared from N,N′-diethylnicotinamide (dena) and Fe(ClO4)3 in ethanol without any addition of HClO4. The proton required for protonation of dena is produced by hydrolysis of aquairon(III) cations. In the crystal structure, cations and anions are held together by ionic interactions. The cations are linked to each other by pyridinium-carbonyl N-H⋯O=C hydrogen bonds and an infinite linear chain along axis a is formed.

scholarly journals Pretreatment of Switchgrass for Production of Glucose via Sulfonic Acid-Impregnated Activated Carbon

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 504
Author(s):  
Yane Ansanay ◽  
Praveen Kolar ◽  
Ratna Sharma-Shivappa ◽  
Jay Cheng ◽  
Consuelo Arellano
Keyword(s):  
Activated Carbon ◽  
Sulfonic Acid ◽  
Solid Acid ◽  
Methanesulfonic Acid ◽  
Biofuel Production ◽  
Acid Catalysts ◽  
Effects Of Temperature ◽  
Carbon Catalysts ◽  
Hydrolysis Of

In the present research, activated carbon-supported sulfonic acid catalysts were synthesized and tested as pretreatment agents for the conversion of switchgrass into glucose. The catalysts were synthesized by reacting sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid with activated carbon. The characterization of catalysts suggested an increase in surface acidities, while surface area and pore volumes decreased because of sulfonation. Batch experiments were performed in 125 mL serum bottles to investigate the effects of temperature (30, 60, and 90 °C), reaction time (90 and 120 min) on the yields of glucose. Enzymatic hydrolysis of pretreated switchgrass using Ctec2 yielded up to 57.13% glucose. Durability tests indicated that sulfonic solid-impregnated carbon catalysts were able to maintain activity even after three cycles. From the results obtained, the solid acid catalysts appear to serve as effective pretreatment agents and can potentially reduce the use of conventional liquid acids and bases in biomass-into-biofuel production.

Characterization of endogenous endopeptidases and exopeptidases and application for the limited hydrolysis of peanut proteins

2021 ◽  
Vol 345 ◽  
pp. 128764
Author(s):  
Yeming Chen ◽  
Hongsheng Zhang ◽  
Caimeng Zhang ◽  
Xiangzhen Kong ◽  
Yufei Hua
Keyword(s):  
Peanut Proteins ◽  
Hydrolysis Of

scholarly journals Multifunctional Biodegradable Vascular PLLA Scaffold with Improved X-ray Opacity, Anti-Inflammation, and Re-Endothelization

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1979
Author(s):  
Ho In Lee ◽  
Yun Heo ◽  
Seung-Woon Baek ◽  
Da-Seul Kim ◽  
Duck Hyun Song ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Inflammatory Responses ◽  
Neointimal Hyperplasia ◽  
Film Surface ◽  
High Mechanical Property ◽  
X Ray ◽  
Stent Restenosis ◽  
X Ray Computed ◽  
Hydrolysis Of

Poly(L-lactic acid) (PLLA) has been used as a biodegradable vascular scaffold (BVS) material due to high mechanical property, biodegradability, and biocompatibility. However, acidic byproducts from hydrolysis of PLLA reduce the pH after the surrounding implanted area and cause inflammatory responses. As a result, severe inflammation, thrombosis, and in-stent restenosis can occur after implantation by using BVS. Additionally, polymers such as PLLA could not find on X-ray computed tomography (CT) because of low radiopacity. To this end, here, we fabricated PLLA films as the surface of BVS and divided PLLA films into two coating layers. At the first layer, PLLA film was coated by 2,3,5-triiodobenzoic acid (TIBA) and magnesium hydroxide (MH) with poly(D,L-lactic acid) (PDLLA) for radiopaque and neutralization of acidic environment, respectively. The second layer of coated PLLA films is composed of polydopamine (PDA) and then cystamine (Cys) for the generation of nitric oxide (NO) release, which is needed for suppression of smooth muscle cells (SMCs) and proliferation of endothelial cells (ECs). The characterization of the film surface was conducted via various analyses. Through the surface modification of PLLA films, they have multifunctional abilities to overcome problems of BVS effectively such as X-ray penetrability, inflammation, thrombosis, and neointimal hyperplasia. These results suggest that the modification of biodegradable PLLA using TIBA, MH, PDA, and Cys will have important potential in implant applications.

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