Faculty Opinions recommendation of A rice family 9 glycoside hydrolase isozyme with broad substrate specificity for hemicelluloses in type II cell walls.

2016 ◽  
Author(s):  
Daniel Cosgrove
Keyword(s):  
Substrate Specificity ◽  
Cell Walls ◽  
Glycoside Hydrolase ◽  
Type Ii ◽  
Broad Substrate Specificity ◽  
Type Ii Cell

scholarly journals The source of inorganic nitrogen has distinct effects on cell wall composition in Brachypodium distachyon

2019 ◽  
Vol 70 (21) ◽  
pp. 6461-6473 ◽  
Author(s):  
Sylwia Głazowska ◽  
Laetitia Baldwin ◽  
Jozef Mravec ◽  
Christian Bukh ◽  
Jonathan U Fangel ◽  
...  
Keyword(s):  
Cell Walls ◽  
Inorganic Nitrogen ◽  
Brachypodium Distachyon ◽  
Crop Model ◽  
Cell Wall Composition ◽  
Type Ii ◽  
Specific Manner ◽  
Type Ii Cell ◽  
Compositional Changes ◽  
Different Sources

Different sources of inorganic nitrogen exert compositional changes on type II cell walls of the grass and crop model Brachypodium distachyon in an organ- and development-specific manner.

scholarly journals Type II Secretion-Dependent Aminopeptidase LapA and Acyltransferase PlaC Are Redundant for Nutrient Acquisition duringLegionella pneumophilaIntracellular Infection of Amoebas

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
pp. e00528-18 ◽  
Author(s):  
Richard C. White ◽  
Felizza F. Gunderson ◽  
Jessica Y. Tyson ◽  
Katherine H. Richardson ◽  
Theo J. Portlock ◽  
...  
Keyword(s):  
Amino Acids ◽  
Substrate Specificity ◽  
Transcriptional Analysis ◽  
Type Ii Secretion ◽  
Major Advance ◽  
Type Ii ◽  
Content Type ◽  
Broad Substrate Specificity ◽  
First Time

ABSTRACTLegionella pneumophilagenes encoding LapA, LapB, and PlaC were identified as the most highly upregulated type II secretion (T2S) genes during infection ofAcanthamoeba castellanii, although these genes had been considered dispensable on the basis of the behavior of mutants lacking eitherlapAandlapBorplaC. AplaCmutant showed even higher levels oflapAandlapBtranscripts, and alapA lapBmutant showed heightening ofplaCmRNA levels, suggesting that the role of the LapA/B aminopeptidase is compensatory with respect to that of the PlaC acyltransferase. Hence, we made double mutants and found thatlapA plaCmutants have an ~50-fold defect during infection ofA. castellanii. These data revealed, for the first time, the importance of LapA in any sort of infection; thus, we purified LapA and defined its crystal structure, activation by another T2S-dependent protease (ProA), and broad substrate specificity. When the amoebal infection medium was supplemented with amino acids, the defect of thelapA plaCmutant was reversed, implying that LapA generates amino acids for nutrition. Since the LapA and PlaC data did not fully explain the role of T2S in infection, we identified, via proteomic analysis, a novel secreted protein (NttD) that promotes infection ofA. castellanii. AlapA plaC nttDmutant displayed an even greater (100-fold) defect, demonstrating that the LapA, PlaC, and NttD data explain, to a significant degree, the importance of T2S. LapA-, PlaC-, and NttD-like proteins had distinct distribution patterns within and outside theLegionellagenus. LapA was notable for having as its closest homologue anA. castellaniiprotein.IMPORTANCETransmission ofL. pneumophilato humans is facilitated by its ability to grow inAcanthamoebaspecies. We previously documented that type II secretion (T2S) promotesL. pneumophilainfection ofA. castellanii. Utilizing transcriptional analysis and proteomics, double and triple mutants, and crystal structures, we defined three secreted substrates/effectors that largely clarify the role of T2S during infection ofA. castellanii. Particularly interesting are the unique functional overlap between an acyltransferase (PlaC) and aminopeptidase (LapA), the broad substrate specificity and eukaryotic-protein-like character of LapA, and the novelty of NttD. Linking LapA to amino acid acquisition, we defined, for the first time, the importance of secreted aminopeptidases in intracellular infection. Bioinformatic investigation, not previously applied to T2S, revealed that effectors originate from diverse sources and distribute within theLegionellagenus in unique ways. The results of this study represent a major advance in understandingLegionellaecology and pathogenesis, bacterial secretion, and the evolution of intracellular parasitism.

scholarly journals Xylanase and Acetyl Xylan Esterase Activities of XynA, a Key Subunit of the Clostridium cellulovorans Cellulosome for Xylan Degradation

2002 ◽  
Vol 68 (12) ◽  
pp. 6399-6402 ◽  
Author(s):  
Akihiko Kosugi ◽  
Koichiro Murashima ◽  
Roy H. Doi
Keyword(s):  
Substrate Specificity ◽  
Glycoside Hydrolase ◽  
Catalytic Domain ◽  
Acetyl Xylan Esterase ◽  
Clostridium Cellulovorans ◽  
Broad Substrate Specificity ◽  
Xylan Degradation ◽  
Hydrolysis Of ◽  
Esterase Activities

ABSTRACT The Clostridium cellulovorans xynA gene encodes the cellulosomal endo-1,4-β-xylanase XynA, which consists of a family 11 glycoside hydrolase catalytic domain (CD), a dockerin domain, and a NodB domain. The recombinant acetyl xylan esterase (rNodB) encoded by the NodB domain exhibited broad substrate specificity and released acetate not only from acetylated xylan but also from other acetylated substrates. rNodB acted synergistically with the xylanase CD of XynA for hydrolysis of acetylated xylan. Immunological analyses revealed that XynA corresponds to a major xylanase in the cellulosomal fraction. These results indicate that XynA is a key enzymatic subunit for xylan degradation in C. cellulovorans.

Isolation and characterisation of the homogalacturonan from type II cell walls of the commelinoid monocot wheat using HF-solvolysis

2003 ◽  
Vol 338 (5) ◽  
pp. 423-431 ◽  
Author(s):  
Nicola Wiethölter ◽  
Barbara Graeßner ◽  
Manfred Mierau ◽  
William G.T. Willats ◽  
J.Paul Knox ◽  
...  
Keyword(s):  
Cell Walls ◽  
Type Ii ◽  
Type Ii Cell

Structural and biochemical basis of a marine bacterial glycoside hydrolase family 2 β-glycosidase with broad substrate specificity

2021 ◽  
Author(s):  
Jian Yang ◽  
Shubo Li ◽  
Yu Liu ◽  
Ru Li ◽  
Lijuan Long
Keyword(s):  
Substrate Specificity ◽  
Glycoside Hydrolase ◽  
Structural Complexity ◽  
Glycoside Hydrolase Family ◽  
Biochemical Basis ◽  
Broad Substrate Specificity ◽  
Biochemical Analyses ◽  
Transformation Of Organic Matter ◽  
Enzymatic Machinery ◽  
Hydrolase Family

Uronic acids are commonly found in marine polysaccharides and increase structural complexity sanand intrinsic recalcitrance to enzymatic attack. The glycoside hydrolase family 2 (GH2) include proteins that target sugar conjugates with hexuronates and are involved in the catabolism and cycling of marine polysaccharides. Here, we reported a novel GH2, Aq GalA from a marine algae-associated Bacteroidetes with broad-substrate specificity. Biochemical analyses revealed that Aq GalA exhibits hydrolyzing activities against β-galacturonide, β-glucuronide, and β-galactopyranoside via retaining mechanisms. We solved the Aq GalA crystal structure in complex with galacturonic acid (GalA) and showed (via mutagenesis) that charge characteristics at uronate-binding subsites controlled substrate selectivity for uronide hydrolysis. Additionally, conformational flexibility of the Aq GalA active site pocket was proposed as a key component for broad substrate enzyme selectivity. Our Aq GalA structural and functional data augments the current understanding of substrate recognition of GH2 enzymes and provided key insights into the bacterial use of uronic acid containing polysaccharides. IMPORTANCE The decomposition of algal glycans driven by marine bacterial communities represents one of the largest heterotrophic transformation of organic matter fueling marine food webs and global carbon cycling. However, our knowledge of the carbohydrate cycling is limited due to structural complexity of marine polysaccharides and the complicated enzymatic machinery of marine microbes. To degrade algal glycan, marine bacteria such as members of Bacteroidetes produce a complex repertoire of carbohydrate-active enzymes (CAZymes) matching the structural specificity of the different carbohydrates. In this study, we investigated an extracellular GH2 β-glycosidase, Aq GalA from a marine Bacteroidetes to identify the key components responsible for glycuronides recognition and hydrolysis. The broad substrate specificity of Aq GalA against glycosides with diverse stereochemical substitutions indicates its potential in processing complex marine polysaccharides. Our findings promote a better understanding of microbially-driven mechanisms of marine carbohydrate cycling.

scholarly journals Covid-19 Interstitial Pneumonia: Histological and Immunohistochemical Features on Cryobiopsies

Respiration ◽  
2021 ◽  
pp. 369-379
Author(s):  
Claudio Doglioni ◽  
Claudia Ravaglia ◽  
Marco Chilosi ◽  
Giulio Rossi ◽  
Alessandra Dubini ◽  
...  
Keyword(s):  
Interstitial Pneumonia ◽  
Diffuse Alveolar Damage ◽  
Alveolar Type ◽  
Type Ii ◽  
Cell Hyperplasia ◽  
Nuclear Expression ◽  
Alveolar Type Ii Cell ◽  
Hyaline Membranes ◽  
Type Ii Cell ◽  
Phosphorylated Stat3

Background: The pathogenetic steps leading to Covid-19 interstitial pneumonia remain to be clarified. Most postmortem studies to date reveal diffuse alveolar damage as the most relevant histologic pattern. Antemortem lung biopsy may however provide more precise data regarding the earlier stages of the disease, providing a basis for novel treatment approaches. Objectives: To ascertain the morphological and immunohistochemical features of lung samples obtained in patients with moderate Covid-19 pneumonia. Methods: Transbronchial lung cryobiopsy was carried out in 12 Covid-19 patients within 20 days of symptom onset. Results: Histopathologic changes included spots of patchy acute lung injury with alveolar type II cell hyperplasia, with no evidence of hyaline membranes. Strong nuclear expression of phosphorylated STAT3 was observed in >50% of AECII. Interalveolar capillaries showed enlarged lumen and were in part arranged in superposed rows. Pulmonary venules were characterized by luminal enlargement, thickened walls, and perivascular CD4+ T-cell infiltration. A strong nuclear expression of phosphorylated STAT3, associated with PD-L1 and IDO expression, was observed in endothelial cells of venules and interstitial capillaries. Alveolar spaces macrophages exhibited a peculiar phenotype (CD68, CD11c, CD14, CD205, CD206, CD123/IL3AR, and PD-L1). Conclusions: Morphologically distinct features were identified in early stages of Covid-19 pneumonia, with epithelial and endothelial cell abnormalities different from either classical interstitial lung diseases or diffuse alveolar damage. Alveolar type II cell hyperplasia was a prominent event in the majority of cases. Inflammatory cells expressed peculiar phenotypes. No evidence of hyaline membranes and endothelial changes characterized by IDO expression might in part explain the compliance and the characteristic pulmonary vasoplegia observed in less-advanced Covid-19 pneumonia.

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