PIP2 and septin control STIM1/Orai1 assembly by regulating cytoskeletal remodeling via a CDC42-WASP/WAVE-ARP2/3 protein complex

The light-harvesting chlorophyll-a/b protein complex (LHC-II) is the most abundant membrane protein in the chloroplasts of green plants where it functions as a molecular antenna of solar energy for photosynthesis. We have grown two-dimensional (2d) crystals of the purified, detergent-solubilized LHC-II . The crystals which measured 5 to 10 μm in diameter were stabilized for electron microscopy by washing with a 0.5% solution of tannin. Electron diffraction patterns of untilted 2d crystals cooled to 130 K showed sharp spots to 3.1 Å resolution. Spot-scan images of 2d crystals were recorded at 160 K with the Berkeley microscope . Images of untilted crystals were processed, using the unbending procedure by Henderson et al . A projection map of the complex at 3.7Å resolution was generated from electron diffraction amplitudes and high-resolution phases obtained by image processing .A difference Fourier analysis with the same image phases and electron diffraction amplitudes recorded of frozen, hydrated specimens showed no significant differences in the 3.7Å projection map. Our tannin treatment therefore does not affect the structural integrity of the complex.

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Use of Antibody to aid Visualization of Protein at the Termini of Bacteriophage Ø29 DNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600002385 ◽

1980 ◽

Vol 38 ◽

pp. 540-541

Author(s):

Dwight Anderson ◽

Charlene Peterson ◽

Gursaran Notani ◽

Bernard Reilly

Keyword(s):

Electron Microscopy ◽

Bacillus Subtilis ◽

Dna Synthesis ◽

Restriction Endonuclease ◽

Protein Complex ◽

Protein Product ◽

Viral Dna ◽

Small Proteins ◽

Antibody Labeling ◽

Subtilis Bacteriophage

The protein product of cistron 3 of Bacillus subtilis bacteriophage Ø29 is essential for viral DNA synthesis and is covalently bound to the 5’-termini of the Ø29 DNA. When the DNA-protein complex is cleaved with a restriction endonuclease, the protein is bound to the two terminal fragments. The 28,000 dalton protein can be visualized by electron microscopy as a small dot and often is seen only when two ends are in apposition as in multimers or in glutaraldehyde-fixed aggregates. We sought to improve the visibility of these small proteins by use of antibody labeling.

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ASSOCIATION BEHAVIOUR OF THE OESTRADIOL-BINDING PROTEIN COMPLEX WITH THE NUCLEAR FRACTION

Acta Endocrinologica ◽

10.1530/acta.0.071s420 ◽

1972 ◽

Vol 71 (2_Suppla) ◽

pp. S420-S438 ◽

Cited By ~ 6

Author(s):

David L. Williams ◽

Jack Gorski

Keyword(s):

Binding Site ◽

Protein Complex ◽

Binding Protein ◽

Nuclear Fraction ◽

Site Saturation ◽

Total Binding

ABSTRACT A number of studies have been carried out to examine the distribution of the oestradiol-binding protein complex between cytosol and nuclear fractions as a function of total binding site saturation. The results of these studies suggest that each binding protein has one binding site for the hormone. In addition, these studies suggest that the interaction of the oestradiol-binding protein complex with the nucleus involves a large number of low affinity association sites.

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Biomolecular Design and Receptor-Ligand Interaction of a Potential Industrial Biocatalsyt: A Thermostable Thermolysin-Phosphoethanolamine-Ca2+ Protein Complex

Journal of Advanced Catalysis Science and Technology ◽

10.15379/2408-9834.2014.01.01.1 ◽

2014 ◽

Vol 1 (1) ◽

pp. 1-5

Author(s):

Mohd Basyaruddin Abdul Rahman ◽

◽

Ahmad Jaafar ◽

Mahiran Basri ◽

Raja Noor Abdul Rahman ◽

...

Keyword(s):

Protein Complex ◽

Ligand Interaction ◽

Receptor Ligand

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Protein Flexibility Catalyzes a Cell Signaling Reaction of the Ras-GAP Complex

10.26434/chemrxiv.9679028 ◽

2019 ◽

Author(s):

Keiei Kumon ◽

Masahiro Higashi ◽

Shinji Saito ◽

Shigehiko Hayashi

Keyword(s):

Cell Signaling ◽

Conformational Changes ◽

Catalytic Reaction ◽

Protein Complex ◽

Enzyme Mechanism ◽

Activation Free Energy ◽

Chemical Catalysis ◽

Simple Chemical ◽

A Cell ◽

Enzyme Molecules

Many enzyme molecules exhibit characteristic global and slow dynamics which furnish them with allostery realizing remarkable molecular functionalities more than simple chemical catalysis. However, molecular mechanism of a catalytic reaction associated with the molecular flexibility of enzymes is not well-understood. Here we report a hybrid molecular simulation study on GTPase activity of a Ras-GAP protein complex for cell signaling termination. We unveiled that extensive conformational changes of the protein complex and exclusion of internal water molecules are induced upon the transition state (TS) formation in the catalytic reaction and significantly lower the reaction activation free energy. We also revealed that tumor-related mutations perturb those conformational changes upon the TS formation, leading to reduction of the catalytic activity. The findings of the remarkably dynamic protein conformation directly linking to the catalytic reaction have broad implications for understanding of enzyme mechanism and for developments of allosteric drugs and novel catalysts.

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