Tag Archives: AFM Probes

Selective oxidation of B800 bacteriochlorophyll a in photosynthetic light-harvesting protein LH2

Engineering chlorophyll (Chl) pigments that are bound to photosynthetic light-harvesting proteins is one promising strategy to regulate spectral coverage for photon capture and to improve the photosynthetic efficiency of these proteins.*

The in situ oxidation of BChl a in light-harvesting protein LH2 from a purple bacterium Rhodoblastus acidophilus by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone demonstrated in the article “Selective oxidation of B800 bacteriochlorophyll a in photosynthetic light-harvesting protein LH2” by Yoshitaka Saga et al. will be useful for engineering photofunctions in natural light-harvesting proteins and for understanding the alteration from BChl pigments in anoxygenic photosynthetic bacteria to Chl pigments in oxygenic organisms in the evolution of photosynthesis.*

The authors observed their sample in 20 mM Tris buffer containing 150 mM NaCl (pH 8.0) using a  home-built frequency modulation AFM ( FM-AFM ) with NANOSENSORS™ PPP-NCHAuD AFM probes.*

Figure 6 from «Selective oxidation of B800 bacteriochlorophyll a in photosynthetic light-harvesting protein LH2” by Y. Saga et al.: FM-AFM images of native LH2 (A) and oxidized LH2 (B) adsorbed on mica taken in 20 mM Tris buffer containing 150 mM NaCl (pH 8.0). Left: wide images. Middle: locally enlarged images of single LH2 proteins. Right: overlapped height-profiles of ten proteins. NANOSENSORS PPP-NCHAuD AFM probes were used.
Figure 6 from «Selective oxidation of B800 bacteriochlorophyll a in photosynthetic light-harvesting protein LH2” by Y. Saga et al.: FM-AFM images of native LH2 (A) and oxidized LH2 (B) adsorbed on mica taken in 20 mM Tris buffer containing 150 mM NaCl (pH 8.0). Left: wide images. Middle: locally enlarged images of single LH2 proteins. Right: overlapped height-profiles of ten proteins.

*Yoshitaka Saga, Kiyoshiro Kawano, Yuji Otsuka, Michie Imanishi, Yukihiro Kimura, Sayaka Matsui & Hitoshi Asakawa
Selective oxidation of B800 bacteriochlorophyll a in photosynthetic light-harvesting protein LH2
Nature, Scientific Reports, volume 9, Article number: 3636 (2019)
DOI: https://doi.org/10.1038/s41598-019-40082-y

Please follow this external link to read the full article: https://www.nature.com/articles/s41598-019-40082-y

Open Access The article “Selective oxidation of B800 bacteriochlorophyll a in photosynthetic light-harvesting protein LH2” by Yoshitaka Saga, Kiyoshiro Kawano, Yuji Otsuka, Michie Imanishi, Yukihiro Kimura, Sayaka Matsui & Hitoshi Asakawa is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Get free NANOSENSORS qp-fast AFM probes at booth 613 at APS March 2019

Are you looking for AFM probes with unsurpassed small variation in spring constant and resonance frequency? Then visit the NanoAndMore USA booth no. 613 at the 2019 APS March Exhibit and get your free sample of NANOSENSORS™ uniqprobe qp-fast AFM probes.

Please have a look at the uniqprobe brochure or the uniqprobe video on Youtube if you would like to learn more about this AFM probes series.

NANOSENSORS uniqprobe qp-fast AFM probe
NANOSENSORS uniqprobe qp-fast AFM probe

Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering

Amyloidogenesis of α-synuclein (αS) is considered to be a pathological phenomenon related to Parkinson’s disease (PD).

In the publication “Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering”  Ghibom Bhak, Soonkoo Lee, Tae-Hwan Kim, Ji-Hye Lee, Jee Eun Yang, Keehyoung Joo, Jooyoung Lee, Kookheon Char and Seung R. Paik have studied one particular type of meta-stable αS oligomers (Meta-αS-Os) since they act as a growing unit to exhibit the accelerated amyloid fibril formation in the presence of external stimuli such as shear force10, temperature change11, pH12, and organic solvents13 which are suspected to alter the structure of Meta-αS-Os into a self-associative state.*

Figure 2 from Ghibom Bhak et al., “Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering” Unit-assembly of Meta-αS-Os. (a) 3-D AFM images of the scattered Meta-αS-Os species and an extended fibrillar structure on the mica surface. Black arrow represents the heat treatment at 80 °C for 30 min. (b) Thio-T binding fluorescence of αS after the centrifugal membrane filtration in the absence or presence of NaCl at various concentrations of 0, 0.015, 0.15, 1.5, 15, and 150 mM. (c) TEM images of the αS oligomers before (i) and after the membrane filtration at various concentrations of 0 (ii), 0.015 (iii), 0.15 (iv), 1.5 (v), 15 (vi) or 150 mM (vii). (d) AFM image showing coexistence of the oligomers and the amyloid fibrils at 1.5 mM NaCl following the membrane filtration. (e) AFM height profile of the oligomeric and fibrillar species. The oligomeric and fibrillar species of αS on the mica were analyzed with AFM in a tapping mode with a Super Sharp AFM probe (SSS-NCHR, NANOSENSORS, Switzerland).
Figure 2 from Ghibom Bhak et al., “Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering”:
Unit-assembly of Meta-αS-Os. (a) 3-D AFM images of the scattered Meta-αS-Os species and an extended fibrillar structure on the mica surface. Black arrow represents the heat treatment at 80 °C for 30 min. (b) Thio-T binding fluorescence of αS after the centrifugal membrane filtration in the absence or presence of NaCl at various concentrations of 0, 0.015, 0.15, 1.5, 15, and 150 mM. (c) TEM images of the αS oligomers before (i) and after the membrane filtration at various concentrations of 0 (ii), 0.015 (iii), 0.15 (iv), 1.5 (v), 15 (vi) or 150 mM (vii). (d) AFM image showing coexistence of the oligomers and the amyloid fibrils at 1.5 mM NaCl following the membrane filtration. (e) AFM height profile of the oligomeric and fibrillar species.

“For the assessment of heat-induced oligomeric unit assembly, an aliquot (10 μl) containing αS oligomers was placed on a cleaved mica surface. Following 30-min incubation at room temperature, the mica was immersed in fresh 20 mM Mes (pH 6.5) and incubated at 80 °C for another 30 min. After the heat-treated mica was cleaned with excessive distillated water, the oligomeric and fibrillar species of αS on the mica were analyzed with AFM in a tapping mode with a Super Sharp AFM tip (SSS-NCHR, NANOSENSORS, Switzerland). To reveal coexistence of the oligomers and fibrils, the αS species (10 μl) was adsorbed on the mica coated with poly-l-lysine for 5 min at room temperature. After the mica was washed with distilled water 5 times and dried in vacuum chamber, AFM analysis was done in a tapping mode.”*

“Meta-αS-Os have played a growing unit for the unit-assembly-based facilitated amyloid fibril formation. Their unit-assembly was examined on the surface of mica immersed in 20 mM Mes (pH 6.5) at 80 °C for 30 min. In the 3-D AFM images, the scattered Meta-αS-Os on the mica surface became aligned with each other to form the extended fibrils following the heat treatment (Fig. 2a). This phenomenon reflects general two-step process of protein-surface interaction showing initial reversible binding of the oligomers to the surface followed by their irreversible stabilization into the amyloid fibrils via the transition of Meta-αS-Os into type-Bon oligomers upon the heat treatment. […] AFM analysis revealed that the particulates and the short fibrils of αS obtained with 1.5 mM NaCl had almost identical height profile with the maximum height of 4 nm (Fig. 2d,e).”*

[…]

“AFM analysis revealed that the particulates and the short fibrils of αS obtained with 1.5 mM NaCl had almost identical height profile with the maximum height of 4 nm (Fig. 2d,e).”*

*Ghibom Bhak, Soonkoo Lee, Tae-Hwan Kim, Ji-Hye Lee, Jee Eun Yang, Keehyoung Joo, Jooyoung Lee, Kookheon Char and Seung R. Paik
Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering
Nature Scientific Reports, volume 8, Article number: 14295 (2018)
DOI: https://doi.org/10.1038/s41598-018-32655-0

Open Access: The article “Morphological Evaluation of Meta-stable Oligomers of α-Synuclein with Small-Angle Neutron Scattering” by  Ghibom Bhak et al. is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.