Penicillin-Binding Protein 1 (PBP1) of Staphylococcus aureus Has Multiple Essential Functions in Cell Division

Bacterial cell division is a complex process requiring the coordination of multiple components to allow the appropriate spatial and temporal control of septum formation and cell scission. *

Peptidoglycan (PG) is the major structural component of the septum, and recent studies by Katarzyna Wacnik et al., in the human pathogen Staphylococcus aureus have revealed a complex, multistage PG architecture that develops during septation. *

Penicillin-binding proteins (PBPs) are essential for the final steps of PG biosynthesis; their transpeptidase activity links the peptide side chains of nascent glycan strands. PBP1 is required for cell division in S. aureus. *

In the article “Penicillin-Binding Protein 1 (PBP1) of Staphylococcus aureus Has Multiple Essential Functions in Cell Division” Katarzyna Wacnik, Vincenzo A. Rao, Xinyue Chen, Lucia Lafage, Manuel Pazos, Simon Booth, Waldemar Vollmer, Jamie K. Hobbs, Richard J. Lewis and Simon J. Foster demonstrate that it has multiple essential functions associated with its enzymatic activity and as a regulator of division. *

Loss of PBP1, or just its C-terminal PASTA domains, results in cessation of division at the point of septal plate formation. The PASTA domains can bind PG and thereby potentially coordinate the cell division process. The transpeptidase activity of PBP1 is also essential, but its loss leads to a strikingly different phenotype of thickened and aberrant septa, which is phenocopied by the morphological effects of adding the PBP1-specific β-lactam, meropenem. Together, these results lead to a model for septal PG synthesis where PBP1 enzyme activity is required for the characteristic architecture of the septum and PBP1 protein molecules enable the formation of the septal plate. *

Bacterial cell wall peptidoglycan is essential, and its synthesis is the target of clinically important antibiotics such as β-lactams. β-lactams target penicillin-binding proteins (PBPs) that assemble new peptidoglycan from its building blocks. *

The human pathogen Staphylococcus aureus only has two essential PBPs that can carry out all the functions necessary for growth and division. *

In the absence of the confounding antibiotic resistance-associated PBP PBP2A, the PBP1 transpeptidase activity is required for cell division, and in the article “Penicillin-Binding Protein 1 (PBP1) of Staphylococcus aureus Has Multiple Essential Functions in Cell Division”, Katarzyna Wacnik et al. state that they have found that it has several essential functions, both as an enzyme and as a coordinator by binding to cell division proteins and to its peptidoglycan product, via its PASTA domains. *

This has led to a new model for cell division with PBP1 responsible for the synthesis of the characteristic architectural features of the septum. *

NanoWorld Ultra-Short Cantilevers for High-Speed AFM of the USC-F0.3-k0.3 AFM probe type (nominal spring constant of 0.3 N/m and resonant frequency (in liquid) of ~150 kHz (300 kHz in air) were used for the Atomic Force Microscopy imaging.

Supplemental Material from Katarzyna Wacnik et al 2022 “Penicillin-Binding Protein 1 (PBP1) of Staphylococcus aureus Has Multiple Essential Functions in Cell Division” FIG S5: Gallery of AFM images of S. aureus Δpbp1, pbp1ΔPASTA, and pbp1*. (A) Diagram of the section through of the cell with progressing septum (top) and AFM topographic images (bottom) of unfinished (i) and closed (ii) septa, parallel to the plane of the image, in SH1000 WT. Sacculi (images to the left, scale bars = 500 nm, data scales [z]: 200 [top] and 250 nm [bottom]) and higher-magnification scans (images to the right, scale bars = 50 nm, data scales [z]: 80 [top] and 40 nm [bottom]) of the boxed areas from the images to the left. (B) AFM topographic images of unfinished septa, parallel to the plane of the image, in Δpbp1 (from left to right, scale bars = 500, 50, and 50 nm; data scales [z] 500, 120, and 150 nm), pbp1ΔPASTA (from left to right, scale bars = 500, 50, and 50 nm; data scales [z] 693, 80, and 100 nm), and pbp1* (from left to right, scale bars = 500, 50, and 50 nm; data scales [z] 500, 80, and 25 nm) grown in the absence of inducer for 2 h. Images to the left are sacculi, while images in the center (1) and to the right (2) are higher-magnification scans of the boxed areas of the images on the left. (C) AFM topographic images (right) of the external nascent ring architecture in SH1000 WT (wt; from top to bottom, scale bars = 500 and 50 nm; data scales [z], 100 and 20 nm) and mutants Δpbp1 (top to bottom, scale bars = 500 and 50 nm; data scales [z], 400 and 60 nm) and pbp1ΔPASTA (from top to bottom, scale bars = 500 and 50 nm; data scales [z], 350 and 100 nm) grown in the absence of inducer for 2 h. The top images are the external surface of sacculi, while the bottom images are higher-magnification scans of the boxed areas of the top images. The arrows indicate piecrusts of the next division plane, which dissects the previous division septum. Arrowheads indicate abnormal features, holes, in the PG ring architecture. On the left is an interpretive diagram of a section through the cell wall (i) and the corresponding external surface (ii) as viewed by AFM. The mature cell wall of a newly separated daughter cell is shown in blue, which has both internally and externally mesh-structured PG. The newly exposed septum has an external ring-structured PG (green) and a mesh-like cytoplasmic facing PG (yellow). Data are representative of two independent experiments. NanoWorld Ultra-Short Cantilevers for High-Speed Atomic Force Microscopy of the USC-F0.3-k0.3 AFM probe type were used.
Supplemental Material from Katarzyna Wacnik et al 2022 “Penicillin-Binding Protein 1 (PBP1) of Staphylococcus aureus Has Multiple Essential Functions in Cell Division” FIG S5: Gallery of AFM images of S. aureus Δpbp1, pbp1ΔPASTA, and pbp1*. (A) Diagram of the section through of the cell with progressing septum (top) and AFM topographic images (bottom) of unfinished (i) and closed (ii) septa, parallel to the plane of the image, in SH1000 WT. Sacculi (images to the left, scale bars = 500 nm, data scales [z]: 200 [top] and 250 nm [bottom]) and higher-magnification scans (images to the right, scale bars = 50 nm, data scales [z]: 80 [top] and 40 nm [bottom]) of the boxed areas from the images to the left. (B) AFM topographic images of unfinished septa, parallel to the plane of the image, in Δpbp1 (from left to right, scale bars = 500, 50, and 50 nm; data scales [z] 500, 120, and 150 nm), pbp1ΔPASTA (from left to right, scale bars = 500, 50, and 50 nm; data scales [z] 693, 80, and 100 nm), and pbp1* (from left to right, scale bars = 500, 50, and 50 nm; data scales [z] 500, 80, and 25 nm) grown in the absence of inducer for 2 h. Images to the left are sacculi, while images in the center (1) and to the right (2) are higher-magnification scans of the boxed areas of the images on the left. (C) AFM topographic images (right) of the external nascent ring architecture in SH1000 WT (wt; from top to bottom, scale bars = 500 and 50 nm; data scales [z], 100 and 20 nm) and mutants Δpbp1 (top to bottom, scale bars = 500 and 50 nm; data scales [z], 400 and 60 nm) and pbp1ΔPASTA (from top to bottom, scale bars = 500 and 50 nm; data scales [z], 350 and 100 nm) grown in the absence of inducer for 2 h. The top images are the external surface of sacculi, while the bottom images are higher-magnification scans of the boxed areas of the top images. The arrows indicate piecrusts of the next division plane, which dissects the previous division septum. Arrowheads indicate abnormal features, holes, in the PG ring architecture. On the left is an interpretive diagram of a section through the cell wall (i) and the corresponding external surface (ii) as viewed by AFM. The mature cell wall of a newly separated daughter cell is shown in blue, which has both internally and externally mesh-structured PG. The newly exposed septum has an external ring-structured PG (green) and a mesh-like cytoplasmic facing PG (yellow). Data are representative of two independent experiments.
*Katarzyna Wacnik, Vincenzo A. Rao, Xinyue Chen, Lucia Lafage, Manuel Pazos, Simon Booth, Waldemar Vollmer, Jamie K. Hobbs, Richard J. Lewis and Simon J. Foster
Penicillin-Binding Protein 1 (PBP1) of Staphylococcus aureus Has Multiple Essential Functions in Cell Division
American Society for Microbiology Journals, (2022) mBio, Vol. 13, No. 4
DOI: https://doi.org/10.1128/mbio.00669-22

The article “Penicillin-Binding Protein 1 (PBP1) of Staphylococcus aureus Has Multiple Essential Functions in Cell Division” by Katarzyna Wacnik, Vincenzo A. Rao, Xinyue Chen, Lucia Lafage, Manuel Pazos, Simon Booth, Waldemar Vollmer, Jamie K. Hobbs, Richard J. Lewis and Simon J. Foster 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 https://creativecommons.org/licenses/by/4.0/.

Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents a serious threat to the health of millions of people. Respiratory viruses such as SARS-CoV-2 can be transmitted via airborne and fomite routes. The latter requires virion adsorption at abiotic surfaces and most likely involves the SARS-CoV-2 spike protein subunit 1 (S1), which is the outermost point of its envelope. Understanding S1 spike protein interaction with fomite surfaces thus represents an important milestone on the road to fighting the spread of COVID-19.*

In the article “Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy “ Yang Xin, Guido Grundmeier and Adrian Keller describe how high-speed atomic force microscopy (HS-AFM) is used to monitor the adsorption of the SARS-CoV-2 spike protein S1 at Al2O3(0001) and TiO2(100) surfaces in situ. *

NanoWorld Ultra-Short Cantilevers of the USC-F0.3-k0.3 AFM probe type were used for the high-speed atomic force microscopy. *

Figure 2 from Yang Xin et al Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy HS-AFM images (1 × 1 μm2) of SARS-CoV-2 spike protein S1 in 10 mM Tris (pH 7.5) adsorbed to a) an Al2O3(0001) and b) a TiO2(100) surface recorded at different time points as indicated. Height scales are 5 nm for the clean substrate surfaces at 0 s and 12 nm for the protein covered surfaces at later time points. Below the HS-AFM images, the corresponding height distribution functions are depicted. The vertical lines in the plots represent the height thresholds applied in the statistical analyses. NanoWorld Ultra-Short Cantilevers of the USC-F0.3-k0.3 AFM probe type were used for the high-speed atomic force microscopy.
Figure 2 from Yang Xin et al Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy
HS-AFM images (1 × 1 μm2) of SARS-CoV-2 spike protein S1 in 10 mM Tris (pH 7.5) adsorbed to a) an Al2O3(0001) and b) a TiO2(100) surface recorded at different time points as indicated. Height scales are 5 nm for the clean substrate surfaces at 0 s and 12 nm for the protein covered surfaces at later time points. Below the HS-AFM images, the corresponding height distribution functions are depicted. The vertical lines in the plots represent the height thresholds applied in the statistical analyses.

*Yang Xin, Guido Grundmeier, Adrian Keller
Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy
Advanced NanoBioMed Research, Volume 1, Issue 2, February 2021, 2000024
DOI: https://doi.org/10.1002/anbr.202000024

Open Access : The article “Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy” by Yang Xin, Guido Grundmeier and Adrian Keller 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 https://creativecommons.org/licenses/by/4.0/.

Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies

In the article “Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies” Alexander Zika and Franziska Gröhn describe the development of a novel reversible multi-switchable system consisting of a cationic polyelectrolyte, a hydroxyflavylium molecule (Flavy), and a photoacid.*

Ternary assemblies with sizes in the hundred-to-few hundred nanometers range in aqueous solution exhibit a multi-addressable size and shape.*

The concept exploits the unique property of the photoacid to form a more highly charged molecule and to switch the Flavy molecule in the same step when excited by light irradiation.*

Due to the network of possible reactions of Flavy, self-assembly can be accessed and triggered in a number of ways.*

While their study focused on the first proof of concept and the relation of molecular and nanoscale switching, a deeper understanding of the molecular binding effects may be considered in future studies.*

The type of the photoacid-based assembly presented in the article bears potential, for example, for delivery where the assembly property changes may provide a desirable transformable platform for tunable and smart transport.*

Atomic force microscopy (AFM) with NanoWorld Ultra-short Cantilevers USC-F0.3-k0.3 in tapping mode was used to investigate the structure.*

Figure 6 from “Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies” by Alexander Zika and Franziska Gröhn: Comparison of cycle I and cycle II in AFM.

*Alexander Zika and Franziska Gröhn
Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies
Beilstein J. Org. Chem. 2021, 17, 166–185.
DOI: https://doi.org/10.3762/bjoc.17.17

Please follow this external link to read the full article: https://www.beilstein-journals.org/bjoc/articles/17/17

Open Access : The article “Multiswitchable photoacid–hydroxyflavylium–polyelectrolyte nano-assemblies” by Alexander Zika and Franziska Gröhn 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 https://creativecommons.org/licenses/by/4.0/.