Biogenesis and Membrane Targeting of Lipoproteins

AbstractModules that switch protein-protein interactions on and off are essential to develop synthetic biology; for example, to construct orthogonal signaling pathways, to control artificial protein structures dynamically, and for protein localization in cells or protocells. In nature, the E. coli MinCDE system couples nucleotide-dependent switching of MinD dimerization to membrane targeting to trigger spatiotemporal pattern formation. Here we present a de novo peptide-based molecular switch that toggles reversibly between monomer and dimer in response to phosphorylation and dephosphorylation. In combination with other modules, we construct fusion proteins that couple switching to lipid-membrane targeting by: (i) tethering a ‘cargo’ molecule reversibly to a permanent membrane ‘anchor’; and (ii) creating a ‘membrane-avidity switch’ that mimics the MinD system but operates by reversible phosphorylation. These minimal, de novo molecular switches have potential applications for introducing dynamic processes into designed and engineered proteins to augment functions in living cells and add functionality to protocells.

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The Lactococcal dgkB (yecE) and dxsA Genes for Lipid Metabolism Are Involved in the Resistance to Cell Envelope-Acting Antimicrobials

International Journal of Molecular Sciences ◽

10.3390/ijms22031014 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1014

Author(s):

Aleksandra Tymoszewska ◽

Tamara Aleksandrzak-Piekarczyk

Keyword(s):

Antimicrobial Peptides ◽

Bacterial Resistance ◽

Antimicrobial Agents ◽

Cytoplasmic Membrane ◽

Cross Resistance ◽

Resistant Bacteria ◽

Membrane Targeting ◽

Nucleotide Polymorphisms ◽

Next Generation ◽

Lipid Ii

The emergence of antibiotic-resistant bacteria led to an urgent need for next-generation antimicrobial agents with novel mechanisms of action. The use of positively charged antimicrobial peptides that target cytoplasmic membrane is an especially promising strategy since essential functions and the conserved structure of the membrane hinder the development of bacterial resistance. Aureocin A53- and enterocin L50-like bacteriocins are highly cationic, membrane-targeting antimicrobial peptides that have potential as next-generation antibiotics. However, the mechanisms of resistance to these bacteriocins and cross-resistance against antibiotics must be examined before application to ensure their safe use. Here, in the model bacterium Lactococcus lactis, we studied the development of resistance to selected aureocin A53- and enterocin L50-like bacteriocins and its correlation with antibiotics. First, to generate spontaneous resistant mutants, L.lactis was exposed to bacteriocin BHT-B. Sequencing of their genomes revealed single nucleotide polymorphisms (SNPs) in the dgkB (yecE) and dxsA genes encoding diacylglycerol kinase and 1-deoxy-D-xylulose 5-phosphate synthase, respectively. Then, selected mutants underwent susceptibility tests with a wide array of bacteriocins and antibiotics. The highest alterations in the sensitivity of studied mutants were seen in the presence of cytoplasmic membrane targeting bacteriocins (K411, Ent7, EntL50, WelM, SalC, nisin) and antibiotics (daptomycin and gramicidin) as well as lipid II cycle-blocking bacteriocins (nisin and Lcn972) and antibiotics (bacitracin). Interestingly, decreased via the SNPs accumulation sensitivity to membrane-active bacteriocins and antibiotics resulted in the concurrently increased vulnerability to bacitracin, carbenicillin, or chlortetracycline. It is suspected that SNPs may result in alterations to the efficiency of the nascent enzymes rather than a total loss of their function as neither deletion nor overexpression of dxsA restored the phenotype observed in spontaneous mutants.

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Membrane targeting cationic antimicrobial peptides

Journal of Colloid and Interface Science ◽

10.1016/j.jcis.2018.10.103 ◽

2019 ◽

Vol 537 ◽

pp. 163-185 ◽

Cited By ~ 56

Author(s):

Daniela Ciumac ◽

Haoning Gong ◽

Xuzhi Hu ◽

Jian Ren Lu

Keyword(s):

Antimicrobial Peptides ◽

Membrane Targeting ◽

Cationic Antimicrobial Peptides

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Pleckstrin homology domains: not just for phosphoinositides

Biochemical Society Transactions ◽

10.1042/bst0320707 ◽

2004 ◽

Vol 32 (5) ◽

pp. 707-711 ◽

Cited By ~ 151

Author(s):

M.A. Lemmon

Keyword(s):

Subcellular Localization ◽

Human Genome ◽

Small Gtpases ◽

Membrane Targeting ◽

Ph Domain ◽

Cellular Membranes ◽

Pleckstrin Homology ◽

Ph Domains ◽

Common Domain ◽

Homology Domains

PH domains (pleckstrin homology domains) are the 11th most common domain in the human genome and are best known for their ability to target cellular membranes by binding specifically to phosphoinositides. Recent studies in yeast have shown that, in fact, this is a property of only a small fraction of the known PH domains. Most PH domains are not capable of independent membrane targeting, and those capable of doing so (approx. 33%) appear, most often, to require both phosphoinositide and non-phosphoinositide determinants for their subcellular localization. Several recent studies have suggested that small GTPases such as ARF family proteins play a role in defining PH domain localization. Some others have described a signalling role for PH domains in regulating small GTPases, although phosphoinositides may also play a role. These findings herald a change in our perspective of PH domain function, which will be significantly more diverse than previously supposed.

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