scholarly journals Homochiral and racemic MicroED structures of a peptide repeat from the ice-nucleation protein InaZ

IUCrJ ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Chih-Te Zee ◽  
Calina Glynn ◽  
Marcus Gallagher-Jones ◽  
Jennifer Miao ◽  
Carlos G. Santiago ◽  
...  
Keyword(s):  
Ab Initio ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Electron Diffraction Data ◽  
Ice Nucleation Protein ◽  
X Ray Crystallography ◽  
New Class ◽  
Left Handed ◽  
Em Method ◽  
Amyloid Assembly

The ice-nucleation protein InaZ from Pseudomonas syringae contains a large number of degenerate repeats that span more than a quarter of its sequence and include the segment GSTSTA. Ab initio structures of this repeat segment, resolved to 1.1 Å by microfocus X-ray crystallography and to 0.9 Å by the cryo-EM method MicroED, were determined from both racemic and homochiral crystals. The benefits of racemic protein crystals for structure determination by MicroED were evaluated and it was confirmed that the phase restriction introduced by crystal centrosymmetry increases the number of successful trials during the ab initio phasing of the electron diffraction data. Both homochiral and racemic GSTSTA form amyloid-like protofibrils with labile, corrugated antiparallel β-sheets that mate face to back. The racemic GSTSTA protofibril represents a new class of amyloid assembly in which all-left-handed sheets mate with their all-right-handed counterparts. This determination of racemic amyloid assemblies by MicroED reveals complex amyloid architectures and illustrates the racemic advantage in macromolecular crystallography, now with submicrometre-sized crystals.

scholarly journals Homochiral and racemic MicroED structures of a peptide from the ice nucleation protein InaZ

2018 ◽  
Author(s):  
Chih-Te Zee ◽  
Calina Glynn ◽  
Marcus Gallagher-Jones ◽  
Jennifer Miao ◽  
Carlos G. Santiago ◽  
...  
Keyword(s):  
Ab Initio ◽  
Pseudomonas Syringae ◽  
Amyloid Fibrils ◽  
Ice Nucleation ◽  
Electron Diffraction Data ◽  
Ice Nucleation Protein ◽  
Water Binding ◽  
X Ray Crystallography ◽  
Left Handed ◽  
Amyloid Assembly

AbstractThe ice nucleation protein InaZ of Pseudomonas syringae contains a large number of degenerate repeats that span more than a quarter of its sequence and include the segment GSTSTA. We determine ab initio structures of this repeat segment, resolved to 1.1Å by microfocus x-ray crystallography and 0.9Å by the cryoEM method MicroED, from both racemic and homochiral crystals. We evaluate the benefits of racemic protein crystals for structure determination by MicroED and confirm that phase restriction introduced by crystal centrosymmetry increases the number of successful trials during ab initio phasing of electron diffraction data. Both homochiral and racemic GSTSTA form amyloid-like protofibrils with labile, corrugated antiparallel beta sheets that mate face to back. The racemic GSTSTA protofibril represents a new class of amyloid assembly in which all left-handed sheets mate with their all right-handed counterparts. Our determination of racemic amyloid assemblies by MicroED reveals complex amyloid architectures and illustrates the racemic advantage in macromolecular crystallography, now with sub-micron sized crystals.SynopsisThe atomic asymmetry, left or right handedness, present in macromolecules and first described by Pasteur in his experiments with tartaric acid, is evident even in complex molecular assemblies like amyloid fibrils. Here, using the cryoEM method MicroED, we show that a segment from the ice nucleation protein InaZ assembles into homochiral and racemic water-binding amyloid protofibrils.

scholarly journals Effects of atmospheric conditions on ice nucleation activity of <i>Pseudomonas</i>

2012 ◽  
Vol 12 (22) ◽  
pp. 10667-10677 ◽  
Author(s):  
E. Attard ◽  
H. Yang ◽  
A.-M. Delort ◽  
P. Amato ◽  
U. Pöschl ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Acidic Ph ◽  
Bacterial Cells ◽  
Atmospheric Conditions ◽  
Ice Nucleation Protein ◽  
Ice Melt ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Although ice nuclei from bacterial origin are known to be efficient at the highest temperatures known for ice catalysts, quantitative data are still needed to assess their role in cloud processes. Here we studied the effects of three typical cloud conditions (i) acidic pH (ii) NO2 and O3 exposure and (iii) UV-A exposure on the ice nucleation activity (INA) of four Pseudomonas strains. Three of the Pseudomonas syringae strains were isolated from cloud water and the phyllosphere and Pseudomonas fluorescens strain CGina-01 was isolated from Antarctic glacier ice melt. Among the three conditions tested, acidic pH caused the most significant effects on INA likely due to denaturation of the ice nucleation protein complex. Exposure to NO2 and O3 gases had no significant or only weak effects on the INA of two P. syringae strains whereas the INA of P. fluorescens CGina-01 was significantly affected. The INA of the third P. syringae strain showed variable responses to NO2 and O3 exposure. These differences in the INA of different Pseudomonas suggest that the response to atmospheric conditions could be strain-specific. After UV-A exposure, a substantial loss of viability of all four strains was observed whereas their INA decreased only slightly. This corroborates the notion that under certain conditions dead bacterial cells can maintain their INA. Overall, the negative effects of the three environmental factors on INA were more significant at the warmer temperatures. Our results suggest that in clouds where temperatures are near 0 °C, the importance of bacterial ice nucleation in precipitation processes could be reduced by some environmental factors.

Synthesis of the N-terminal of the Ice Nucleation Protein Gene of Pseudomonas syringae by Assembly PCR

2005 ◽  
Vol 4 (3) ◽  
pp. 187-193 ◽  
Author(s):  
Mohammed A.A. Sarhan . ◽  
Mustaffa Musa . ◽  
Norazmi Mohd Nor . ◽  
Zainul F. Zainuddin .
Keyword(s):  
Pseudomonas Syringae ◽  
Protein Gene ◽  
Ice Nucleation ◽  
Ice Nucleation Protein ◽  
Assembly Pcr

Expression of Carboxymethylcellulase on the Surface of Escherichia Coli Using Pseudomonas Syringae Ice Nucleation Protein

1998 ◽  
Vol 22 (5) ◽  
pp. 348-354 ◽  
Author(s):  
Heung-Chae Jung ◽  
Joon-Hyun Park ◽  
Seung-Hwan Park ◽  
Jean-Michel Lebeault ◽  
Jae-Gu Pan
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Ice Nucleation Protein

scholarly journals Complete Genome Sequence of Pseudomonas syringae BIM B-268, a Plant Pathogen Strain Used for In Vitro Testing of Agricultural Bacteriophage Efficiency

2021 ◽  
Vol 10 (26) ◽  
Author(s):  
Rustam M. Buzikov ◽  
Tatsiana A. Pilipchuk ◽  
Leonid N. Valentovich ◽  
Emilia I. Kalamiyets ◽  
Andrey M. Shadrin
Keyword(s):  
Pseudomonas Syringae ◽  
Genome Sequence ◽  
Ice Nucleation ◽  
Secretion Systems ◽  
Ice Nucleation Protein ◽  
Circular Chromosome ◽  
Content Type ◽  
Genes Encoding ◽  
Single Circular Chromosome

Pseudomonas syringae BIM B-268 is the strain used for in vitro testing of the efficiency of Multiphage, a bacteriophage-based biopesticide produced in Belarus. The genome sequence of this strain consists of a single circular chromosome harboring the genes encoding the ice nucleation protein, syringopeptin biosynthesis, and types III and VI secretion systems.

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