Article
Microbiology
Emmanuele Severi, Mariana Bunoro Batista, Adelie Lannoy, Phillip J. Stansfeld, Tracy Palmer
Summary: The twin arginine transport (Tat) pathway is a mechanism in prokaryotes and chloroplasts that exports folded proteins across membranes. Through mutagenesis experiments, it has been found that a binding site located in the sixth transmembrane helix is crucial for the binding of TatA.
Article
Biochemical Research Methods
Joshua Diaz, Miles Pietsch, Marissa Davila, Gerardo Jaimes, Alexis Hudson, Jean-Philippe Pellois
Summary: This study examines the impact of payload conjugation on the cell-penetrating activity of dfTAT. The results show that smaller payloads have little effect on dfTAT's cell delivery activity, while larger payloads significantly reduce both its endocytic uptake and endosomal escape efficiency.
BIOCONJUGATE CHEMISTRY
(2023)
Article
Immunology
Elia Riquelme, Sabina Omarova, Berengere Ize, David O'Callaghan
Summary: Bacteria use the Tat system to export folded proteins. The Tat system is essential for the pathogen Brucella spp. By bioinformatic screening, 28 B. suis proteins with putative Tat signal sequences were identified.
INFECTION AND IMMUNITY
(2023)
Review
Physiology
Sharbani Kaushik, Haoze He, Ross E. Dalbey
Summary: This review summarizes the crucial role of signal peptides in protein export and membrane protein insertion, as well as their function as key factors for protein targeting and translocation machinery activation. The importance of signal peptide removal and degradation, as well as the emerging research on signal peptidases as novel targets for antibiotic development, are also discussed.
FRONTIERS IN PHYSIOLOGY
(2022)
Article
Microbiology
Klaudia Arauzo-Aguilera, Mirva J. Saaranen, Colin Robinson, Lloyd W. Ruddock
Summary: High-value heterologous proteins with disulfide bonds are typically targeted to the periplasm via the Sec pathway, but the Tat system shows potential as an alternative because it can transport fully folded proteins. Previous studies using the TorA signal peptide, a Tat-specific signal peptide, resulted in lower yields and protein degradation. This study demonstrates that the Tat pathway, specifically through the MdoD and AmiC signal peptides, can export the disulfide bond-containing protein YebF to the periplasm and media at high levels.
Article
Multidisciplinary Sciences
Diego Munoz-Gacitua, Fanny Guzman, Boris Weiss-Lopez
Summary: Crossing the cellular membrane is a major barrier in drug discovery, and cell-penetrating peptides are considered a promising solution. This study finds the equilibrium structure of a hydrophobic penetrating peptide and reveals a two-step mechanism for it to translocate the membrane.
SCIENTIFIC REPORTS
(2022)
Article
Biotechnology & Applied Microbiology
Wenyu Li, Fan Yin, Zixuan Bu, Yuying Liu, Yongqing Zhang, Xiabing Chen, Shaowen Li, Lu Li, Rui Zhou, Qi Huang
Summary: This study constructed a live bacterial vector vaccine using an engineered E. coli strain and demonstrated its efficacy in protecting against Streptococcus suis by utilizing the Tat system and a defective outer membrane. The findings offer a new alternative for developing S. suis vaccines.
JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
May N. Taw, Jason T. Boock, Belen Sotomayor, Daniel Kim, Mark A. Rocco, Dujduan Waraho-Zhmayev, Matthew P. DeLisa
Summary: The study suggests that the Tat translocase may use molecular chaperones to monitor the conformational status of its substrates, with the TatB component playing a key role in sensing the folding state of Tat substrates.
SCIENTIFIC REPORTS
(2022)
Article
Biochemistry & Molecular Biology
Binhan Hao, Wenjie Zhou, Steven M. Theg
Summary: The TMH lengths of TatA and TatB are evolutionarily tuned to 15 amino acids, with activity dropping off following any modification of this length. Even with as few as 11 residues, TatA and TatB can still insert into the membrane bilayer, albeit with a decline in membrane integrity. These findings support a model of Tat transport utilizing toroidal pores formed when the membrane bilayer reaches a critical threshold.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2022)
Article
Biochemistry & Molecular Biology
Wenjie Zhou, Binhan Hao, Terry M. Bricker, Steven M. Theg
Summary: The twin arginine translocation (Tat) pathway plays an important role in protein transport in bacteria, archaea, and plants. By using a real-time luminescence assay, this study reveals that both Delta psi and Delta pH contribute energetically to Tat transport in Escherichia coli spheroplasts.
JOURNAL OF BIOLOGICAL CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Dries Smets, Alexandra Tsirigotaki, Jochem H. Smit, Srinath Krishnamurthy, Athina G. Portaliou, Anastassia Vorobieva, Wim Vranken, Spyridoula Karamanou, Anastassios Economou
Summary: This study investigates the delayed folding mechanism and the regulatory role of signal peptides in the Sec pathway. By comparing two homologous proteins, PpiA and PpiB, it is found that PpiA folds slower and the folding process involves hierarchical foldons. The folding of PpiA is delayed by less hydrophobic native contacts, frustrated residues, and a beta-turn in the earliest foldon, as well as by signal peptide-mediated disruption of foldon hierarchy. Additionally, grafting selected residues or the signal peptide of PpiA onto PpiB converts it into a slow folder with enhanced in vivo secretion. These structural adaptations facilitate protein trafficking.
Article
Agriculture, Dairy & Animal Science
Yan Ma, Zhiyi Guo, Qiujue Wu, Binyao Cheng, Zhenhan Zhai, Yuqin Wang
Summary: This study found that nutrition restriction can reduce the ovarian antioxidant capability in ewes, while supplementation of arginine can significantly improve it, which is associated with the Nrf2/Keap1 pathway.
Article
Biochemistry & Molecular Biology
Qilang Wei, Zhenwei Yan, Yifan Xiong, Zhongming Fang
Summary: The study reveals that the amino acid transporter OsAAP3 is involved in the regulation of lesion mimic and leaf senescence in rice plants. Altering the expression of OsAAP3 can initiate the nitric oxide signaling pathway, impacting various physiological indicators in rice leaves and ultimately leading to cell death and leaf senescence.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Microbiology
Bifang Hao, Lin Liu, Na Liu, Luping Sun, Fengxiu Fan, Jinshan Huang
Summary: In this study, we revealed that BmNPV GP64 retains its signal peptide in host cells, which is crucial for GP64 secretion across the cytomembrane. This study unveils the mechanism of signal peptide in protein targeting and provides important mechanistic understanding of BmNPV infection and host range specificity.
MICROBIOLOGY SPECTRUM
(2022)
Review
Plant Sciences
Sergey M. Rozov, Elena Deineko
Summary: This article introduces different approaches for increasing the yield of recombinant proteins, including transporting the target protein to cell compartments with low protease activity. The mechanisms of protein targeting, types and structures of signal peptide sequences, and the impact of protein targeting on yield are discussed, along with the search for signal sequences based on their primary structure.
Article
Microbiology
Marilia de Assis Alcoforado Costa, Richard A. Owen, Triin Tammsalu, Grant Buchanan, Tracy Palmer, Frank Sargent
Review
Biochemistry & Molecular Biology
Tracy Palmer, Phillip J. Stansfeld
MOLECULAR MICROBIOLOGY
(2020)
Article
Biochemistry & Molecular Biology
Tracy Palmer, Alexander J. Finney, Chayan Kumar Saha, Gemma C. Atkinson, Frank Sargent
Summary: Gram-negative bacteria have evolved various pathways to secrete proteins, with the involvement of holins and cell wall-editing enzymes. The identity of the cell wall-editing enzymes varies across different biological systems, indicating that the secretion pathway may have evolved multiple times. Genomic analysis supports the conservation of this pathway, which is implicated in the secretion of hydrolytic enzymes and toxins in a range of bacteria.
MOLECULAR MICROBIOLOGY
(2021)
Article
Genetics & Heredity
Felicity Alcock, Tracy Palmer
Article
Microbiology
Rory Hennell James, Justin C. Deme, Andreas Kjaer, Felicity Alcock, Augustinas Silale, Frederic Lauber, Steven Johnson, Ben C. Berks, Susan M. Lea
Summary: The study reveals the internal structure and working mechanism of the gliding motility/type 9 protein secretion system motor, demonstrating that proton flow results in rotation of the GldM/PorM dimer inside the intra-membrane ring to drive processes at the bacterial outer membrane.
NATURE MICROBIOLOGY
(2021)
Article
Microbiology
Kieran Bowran, Tracy Palmer
Summary: The study reveals genetic diversity in T7SS-encoding genes and substrate proteins across Listeria monocytogenes species, with EssC variants correlated with distinct subsets of genes for likely substrates and accessory proteins. The findings strongly suggest an important role of T7SS in bacterial antagonism in this species.
Article
Biochemistry & Molecular Biology
Augustinas Silale, Susan M. Lea, Ben C. Berks
Summary: During natural transformation, bacteria import extracellular DNA molecules into their genome using the protein ComEC. The C-terminal domain (CTD) of ComEC binds Mn2+ ions and exhibits Mn2+-dependent phosphodiesterase and nuclease activities. Inactivation of the CTD's enzymatic activity severely inhibits natural transformation in Bacillus subtilis.
MOLECULAR MICROBIOLOGY
(2021)
Article
Genetics & Heredity
Emmanuele Severi, Michelle Rudden, Andrew Bell, Tracy Palmer, Nathalie Juge, Gavin H. Thomas
Summary: Sialic acids at cell surface glycoconjugates are easily liberated by sialidase enzymes and used as metabolites by numerous bacteria, especially pathogens and commensals living on mucosal surfaces. Specific bacterial transporters are needed for the acquisition of host-derived sialic acids, and they have independently evolved at least eight times within major families/superfamilies of bacterial transporters. The discovery of new sialic acid-specific transporters in diverse bacteria, including previously unrecognized species, suggests a strong evolutionary selection for the emergence of sialic acid specificity within existing transporter architectures.
MICROBIAL GENOMICS
(2021)
Article
Microbiology
Rory Hennell James, Justin C. Deme, Alicia Hunter, Ben C. Berks, Susan M. Lea
Summary: Gliding motility and protein secretion through the type IX secretion system (T9SS) are two specific features of the Bacteroidetes. These processes are energized by the GldLM motor complex, which converts the proton motive force into mechanical work. The structures of the GldLM motor complex from different Bacteroidetes species reveal a conserved architecture, but with species-specific differences at the N terminus of GldL. This study enhances our understanding of bacterial ion-driven motors and their role in T9SS and gliding motility.
Article
Genetics & Heredity
Stephen R. Garrett, Giuseppina Mariano, Jo Dicks, Tracy Palmer
Summary: Homologous recombination plays a significant role in the evolution of T7SS immunity gene clusters. The esaG and tsaI genes in Staphylococcus aureus and Streptococcus species exhibit polymorphisms, and evidence of recombination events between conserved sequence blocks explains the variation in gene repertoires.
MICROBIAL GENOMICS
(2022)
Article
Biochemistry & Molecular Biology
Felicity Alcock, Ben C. Berks
Summary: This study reports the recovery of receptor complexes associated with elevated levels of TatA through detergent solubilization of membranes during active transport. By combining biochemical analysis and live cell fluorescence imaging, sub-steps in the Tat translocation cycle were resolved, and it was inferred that TatA assembly precedes the functional interaction with TatC. It was also observed that dissipation of the protonmotive force releases TatA oligomers from the assembled translocation site, suggesting that the TatA oligomer is assembled at the periphery of the receptor complex.
MOLECULAR MICROBIOLOGY
(2022)
Editorial Material
Multidisciplinary Sciences
Ben C. Berks
Summary: Membrane-spanning proteins play crucial roles in cells, and new findings challenge our current understanding of how these proteins are inserted into the membranes of animal cells.
Article
Microbiology
Micaela Mossop, Luca Robinson, Jhih-Hang Jiang, Anton Y. Peleg, Luke Blakeway, Nenad Macesic, Audrey Perry, Stephen Bourke, Fatima R. Ulhuq, Tracy Palmer
Summary: One third of CF patients in the UK are co-infected with both Staphylococcus aureus and Pseudomonas aeruginosa, which contribute to lung tissue destruction and respiratory failure. This study aims to characterize twenty-five clinical S. aureus isolates from CF patients, including those with mono- and coinfection with P. aeruginosa, using molecular and phenotypic tools.
JOURNAL OF MEDICAL MICROBIOLOGY
(2023)
Article
Microbiology
Emmanuele Severi, Mariana Bunoro Batista, Adelie Lannoy, Phillip J. Stansfeld, Tracy Palmer
Summary: The twin arginine transport (Tat) pathway is a mechanism in prokaryotes and chloroplasts that exports folded proteins across membranes. Through mutagenesis experiments, it has been found that a binding site located in the sixth transmembrane helix is crucial for the binding of TatA.
Article
Genetics & Heredity
Kieran Bowran, Stephen R. Garrett, Arnoud H. M. van Vliet, Tracy Palmer
Summary: The type VIIb protein secretion system (T7SSb) is a competitive mechanism found in Bacillota bacteria. EssC, a crucial component of T7SSb, plays a significant role in substrate recognition. Analysis of Listeria monocytogenes genomes reveals that EssC has seven sequence variants, each associated with specific candidate substrate proteins.
MICROBIAL GENOMICS
(2023)