Biogenesis of a bacterial metabolosome for propanediol utilization

Bacterial metabolosomes are a family of protein organelles in bacteria. Elucidating how thousands of proteins self-assemble to form functional metabolosomes is essential for understanding their significance in cellular metabolism and pathogenesis. Here we investigate the de novo biogenesis of propanediol-utilization (Pdu) metabolosomes and characterize the roles of the key constituents in generation and intracellular positioning of functional metabolosomes. Our results demonstrate that the Pdu metabolosome undertakes both 'Shell first' and 'Cargo first' assembly pathways, unlike the beta-carboxysome structural analog which only involves the 'Cargo first' strategy. Shell and cargo assemblies occur independently at the cell poles. The internal cargo core is formed through the ordered assembly of multiple enzyme complexes, and exhibits liquid-like properties within the metabolosome architecture. Our findings provide mechanistic insight into the molecular principles driving bacterial metabolosome assembly and expand our understanding of liquid-like organelle biogenesis.

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Reaction Kinetics Direct a Rational Synthesis of an HIV-1 Inactivator of Nucleocapsid Protein 7 and Provide Mechanistic Insight into Cellular Metabolism and Antiviral Activity

Chemistry - A European Journal ◽

10.1002/chem.201802752 ◽

2018 ◽

Vol 24 (38) ◽

pp. 9440-9440

Author(s):

Herman Nikolayevskiy ◽

Michael T. Scerba ◽

Jeffrey R. Deschamps ◽

Daniel H. Appella

Keyword(s):

Antiviral Activity ◽

Reaction Kinetics ◽

Nucleocapsid Protein ◽

Cellular Metabolism ◽

Mechanistic Insight ◽

Insight Into ◽

Hiv 1

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Front Cover: Reaction Kinetics Direct a Rational Synthesis of an HIV-1 Inactivator of Nucleocapsid Protein 7 and Provide Mechanistic Insight into Cellular Metabolism and Antiviral Activity (Chem. Eur. J. 38/2018)

Chemistry - A European Journal ◽

10.1002/chem.201802620 ◽

2018 ◽

Vol 24 (38) ◽

pp. 9436-9436

Author(s):

Herman Nikolayevskiy ◽

Michael T. Scerba ◽

Jeffrey R. Deschamps ◽

Daniel H. Appella

Keyword(s):

Antiviral Activity ◽

Reaction Kinetics ◽

Nucleocapsid Protein ◽

Cellular Metabolism ◽

Front Cover ◽

Mechanistic Insight ◽

Insight Into ◽

Hiv 1

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De Novo Assessment and Review of Pan-American Pit Viper Anticoagulant and Procoagulant Venom Activities via Kinetomic Analyses

Toxins ◽

10.3390/toxins11020094 ◽

2019 ◽

Vol 11 (2) ◽

pp. 94 ◽

Cited By ~ 8

Author(s):

Vance G. Nielsen ◽

Nathaniel Frank ◽

Sam Afshar

Keyword(s):

South America ◽

Central America ◽

De Novo ◽

Inhibit Activity ◽

North Central ◽

Mechanistic Insight ◽

Carrier Molecule ◽

Pan American ◽

Insight Into

Snakebite with hemotoxic venom continues to be a major source of morbidity and mortality worldwide. Our laboratory has characterized the coagulopathy that occurs in vitro in human plasma via specialized thrombelastographic methods to determine if venoms are predominantly anticoagulant or procoagulant in nature. Further, the exposure of venoms to carbon monoxide (CO) or O-phenylhydroxylamine (PHA) modulate putative heme groups attached to key enzymes has also provided mechanistic insight into the multiple different activities contained in one venom. The present investigation used these techniques to characterize fourteen different venoms obtained from snakes from North, Central, and South America. Further, we review and present previous thrombelastographic-based analyses of eighteen other species from the Americas. Venoms were found to be anticoagulant and procoagulant (thrombin-like activity, thrombin-generating activity). All prospectively assessed venom activities were determined to be heme-modulated except two, wherein both CO and its carrier molecule were found to inhibit activity, while PHA did not affect activity (Bothriechis schlegelii and Crotalus organus abyssus). When divided by continent, North and Central America contained venoms with mostly anticoagulant activities, several thrombin-like activities, with only two thrombin-generating activity containing venoms. In contrast, most venoms with thrombin-generating activity were located in South America, derived from Bothrops species. In conclusion, the kinetomic profiles of venoms obtained from thirty-two Pan-American Pit Viper species are presented. It is anticipated that this approach will be utilized to identify clinically relevant hemotoxic venom enzymatic activity and assess the efficacy of locally delivered CO or systemically administered antivenoms.

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MreB Drives De Novo Rod Morphogenesis in Caulobacter crescentus via Remodeling of the Cell Wall

Journal of Bacteriology ◽

10.1128/jb.01311-09 ◽

2009 ◽

Vol 192 (6) ◽

pp. 1671-1684 ◽

Cited By ~ 78

Author(s):

Constantin N. Takacs ◽

Sebastian Poggio ◽

Godefroid Charbon ◽

Mathieu Pucheault ◽

Waldemar Vollmer ◽

...

Keyword(s):

High Performance ◽

Culture Medium ◽

De Novo ◽

Caulobacter Crescentus ◽

Morphological Changes ◽

Bacterial Species ◽

Membrane Vesicles ◽

Structural Analog ◽

Outer Membrane Vesicles ◽

Insight Into

ABSTRACT MreB, the bacterial actin-like cytoskeleton, is required for the rod morphology of many bacterial species. Disruption of MreB function results in loss of rod morphology and cell rounding. Here, we show that the widely used MreB inhibitor A22 causes MreB-independent growth inhibition that varies with the drug concentration, culture medium conditions, and bacterial species tested. MP265, an A22 structural analog, is less toxic than A22 for growth yet equally efficient for disrupting the MreB cytoskeleton. The action of A22 and MP265 is enhanced by basic pH of the culture medium. Using this knowledge and the rapid reversibility of drug action, we examined the restoration of rod shape in lemon-shaped Caulobacter crescentus cells pretreated with MP265 or A22 under nontoxic conditions. We found that reversible restoration of MreB function after drug removal causes extensive morphological changes including a remarkable cell thinning accompanied with elongation, cell branching, and shedding of outer membrane vesicles. We also thoroughly characterized the composition of C. crescentus peptidoglycan by high-performance liquid chromatography and mass spectrometry and showed that MreB disruption and recovery of rod shape following restoration of MreB function are accompanied by considerable changes in composition. Our results provide insight into MreB function in peptidoglycan remodeling and rod shape morphogenesis and suggest that MreB promotes the transglycosylase activity of penicillin-binding proteins.

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