scholarly journals MreC and MreD balance the interaction between the elongasome proteins PBP2 and RodA

PLoS Genetics ◽  
2020 ◽  
Vol 16 (12) ◽  
pp. e1009276
Author(s):  
Xiaolong Liu ◽  
Jacob Biboy ◽  
Elisa Consoli ◽  
Waldemar Vollmer ◽  
Tanneke den Blaauwen
Keyword(s):  
Crystal Structure ◽  
Cell Wall ◽  
Catalytic Activity ◽  
Cylindrical Part ◽  
Model System ◽  
Essential Proteins ◽  
Antibiotic Drug ◽  
Interaction Change ◽  
New Strategies

Rod-shape of most bacteria is maintained by the elongasome, which mediates the synthesis and insertion of peptidoglycan into the cylindrical part of the cell wall. The elongasome contains several essential proteins, such as RodA, PBP2, and the MreBCD proteins, but how its activities are regulated remains poorly understood. Using E. coli as a model system, we investigated the interactions between core elongasome proteins in vivo. Our results show that PBP2 and RodA form a complex mediated by their transmembrane and periplasmic parts and independent of their catalytic activity. MreC and MreD also interact directly with PBP2. MreC elicits a change in the interaction between PBP2 and RodA, which is suppressed by MreD. The cytoplasmic domain of PBP2 is required for this suppression. We hypothesize that the in vivo measured PBP2-RodA interaction change induced by MreC corresponds to the conformational change in PBP2 as observed in the MreC-PBP2 crystal structure, which was suggested to be the “on state” of PBP2. Our results indicate that the balance between MreC and MreD determines the activity of PBP2, which could open new strategies for antibiotic drug development.

scholarly journals MreC and MreD balance the interaction between the elongasome proteins PBP2 and RodA

2019 ◽  
Author(s):  
Xiaolong Liu ◽  
Jacob Biboy ◽  
Waldemar Vollmer ◽  
Tanneke den Blaauwen
Keyword(s):  
Conformational Change ◽  
Conformational Changes ◽  
Cell Envelope ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Cylindrical Part ◽  
E Coli ◽  
Length Growth ◽  
Antibiotic Drug

AbstractRod-shape of most bacteria is maintained by the elongasome, which mediates the synthesis and insertion of peptidoglycan into the cylindrical part of the cell wall. The elongasome contains several essential proteins, such as RodA, PBP2, and the MreBCD proteins, but how its activities are regulated remains poorly understood. Using E. coli as a model system, we investigated the interactions between core elongasome proteins in vivo. Our results show that PBP2 and RodA form a complex mediated by their transmembrane and periplasmic parts and independent of their catalytic activity. MreC and MreD also interact directly with PBP2. MreC elicits a chance in the interaction between PBP2 and RodA, which is suppressed by MreD. The cytoplasmic domain of PBP2 is required for this suppression. We hypothesize that the in vivo measured PBP2-RodA interaction change induced by MreC corresponds to the conformational change in PBP2 as observed in the MreC-PBP2 crystal structure, which was suggested to be the “on state” of PBP2. Our results indicate that the balance between MreC and MreD determines the activity of PBP2, which could open new strategies for antibiotic drug development.ImportanceThe cell envelope of Escherichia coli bears the protective and shape-determining peptidoglycan layer sandwiched between the outer and inner membranes. Length growth in bacteria is accomplished by a protein complex termed elongasome. We used Förster Resonance Energy Transfer (FRET) that reports not only on whether proteins interact with each other but also on conformational changes during interactions, to investigate how the elongasome might be activated. RodA and PBP2 provide the peptidoglycan glycosyltransferase and transpeptidase activities needed to synthesize new peptidolgycan during length growth, respectively, and PBP2 activates RodA. We show that the interactions between MreC and MreD with PBP2-RodA alter the nature of the interaction between PBP2 and RodA and hypothesis that the corresponding conformational change in the PBP2-RodA complex allows switching between the ‘on’ and ‘off’ states of the elongasome.

scholarly journals Nuclear congression is driven by cytoplasmic microtubule plus end interactions in S. cerevisiae

2005 ◽  
Vol 172 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Jeffrey N. Molk ◽  
E.D. Salmon ◽  
Kerry Bloom
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Binding Proteins ◽  
Budding Yeast ◽  
Model System ◽  
Organelle Transport ◽  
Nuclear Movement ◽  
Cytoplasmic Microtubule ◽  
Cell Wall Breakdown

Nuclear movement before karyogamy in eukaryotes is known as pronuclear migration or as nuclear congression in Saccharomyces cerevisiae. In this study, S. cerevisiae is used as a model system to study microtubule (MT)-dependent nuclear movements during mating. We find that nuclear congression occurs through the interaction of MT plus ends rather than sliding and extensive MT overlap. Furthermore, the orientation and attachment of MTs to the shmoo tip before cell wall breakdown is not required for nuclear congression. The MT plus end–binding proteins Kar3p, a class 14 COOH-terminal kinesin, and Bik1p, the CLIP-170 orthologue, localize to plus ends in the shmoo tip and initiate MT interactions and depolymerization after cell wall breakdown. These data support a model in which nuclear congression in budding yeast occurs by plus end MT capture and depolymerization, generating forces sufficient to move nuclei through the cytoplasm. This is the first evidence that MT plus end interactions from oppositely oriented organizing centers can provide the force for organelle transport in vivo.

scholarly journals Crystal structure of Arabidopsis thaliana casein kinase 2 α1

2020 ◽  
Vol 76 (4) ◽  
pp. 182-191
Author(s):  
Manon Demulder ◽  
Lieven De Veylder ◽  
Remy Loris
Keyword(s):  
Crystal Structure ◽  
Arabidopsis Thaliana ◽  
Model System ◽  
Casein Kinase ◽  
Casein Kinase 2 ◽  
Body Motion ◽  
Biological Functions ◽  
Α Subunit ◽  
Crystal Forms

Casein kinase 2 (CK2) is a ubiquitous pleiotropic enzyme that is highly conserved across eukaryotic kingdoms. CK2 is singular amongst kinases as it is highly rigid and constitutively active. Arabidopsis thaliana is widely used as a model system in molecular plant research; the biological functions of A. thaliana CK2 are well studied in vivo and many of its substrates have been identified. Here, crystal structures of the α subunit of A. thaliana CK2 in three crystal forms and of its complex with the nonhydrolyzable ATP analog AMppNHp are presented. While the C-lobe of the enzyme is highly rigid, structural plasticity is observed for the N-lobe. Small but significant displacements within the active cleft are necessary in order to avoid steric clashes with the AMppNHp molecule. Binding of AMppNHp is influenced by a rigid-body motion of the N-lobe that was not previously recognized in maize CK2.

scholarly journals Biochemical and structural insights into the activation of PBP1b by the essential domain of FtsN

2020 ◽  
Author(s):  
Adrien Boes ◽  
Frederic Kerff ◽  
Raphael Herman ◽  
Thierry Touze ◽  
Eefjan Breukink ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Escherichia Coli ◽  
Cell Wall ◽  
Cell Division ◽  
Binding Pocket ◽  
Nonpermissive Temperature ◽  
Multiprotein Complex ◽  
Division Site ◽  
Structural Insights

AbstractPeptidoglycan (PG) is an essential constituent of the bacterial cell wall. During cell division PG synthesis localizes at mid-cell under the control of a multiprotein complex, the divisome. In Escherichia coli, septal PG synthesis and cell constriction rely on the accumulation of FtsN at the division site. The region L75 to Q93 of FtsN (EFtsN) was shown to be essential and sufficient for its functioning in vivo but the specific target and the molecular mechanism remained unknown. Here, we show that EFtsN binds specifically to the major PG synthase PBP1b and is sufficient to stimulate its GTase activity. We also report the crystal structure of PBP1b in complex with EFtsN which provides structural insights into the mode of binding of EFtsN at the junction between the GTase and UB2H domains of PBP1b. Interestingly, the mutations R141A/R397A of PBP1b, within the EFtsN binding pocket, reduce the activation of PBP1b by FtsN. This mutant was unable to rescue ΔponB-ponAts strain at nonpermissive temperature and induced a mild cell chaining phenotype and cell lysis. Altogether, the results show that PBP1b is a target of EFtsN and suggest that binding of FtsN to PBP1b contributes to trigger septal PG synthesis and cell constriction.

Crystal structures of UDP-N-acetylmuramic acid L-alanine ligase (MurC) from Mycobacterium bovis with and without UDP-N-acetylglucosamine

2021 ◽  
Vol 77 (5) ◽  
pp. 618-627
Author(s):  
Pil-Won Seo ◽  
Suk-Youl Park ◽  
Andreas Hofmann ◽  
Jeong-Sun Kim
Keyword(s):  
Crystal Structure ◽  
Cell Wall ◽  
Catalytic Activity ◽  
Amino Acid ◽  
Mycobacterium Bovis ◽  
Domain Architecture ◽  
Binding Domain ◽  
Cross Linking ◽  
Nickel Ion ◽  
Binding Loop

Peptidoglycan comprises repeating units of N-acetylmuramic acid, N-acetylglucosamine and short cross-linking peptides. After the conversion of UDP-N-acetylglucosamine (UNAG) to UDP-N-acetylmuramic acid (UNAM) by the MurA and MurB enzymes, an amino acid is added to UNAM by UDP-N-acetylmuramic acid L-alanine ligase (MurC). As peptidoglycan is an essential component of the bacterial cell wall, the enzymes involved in its biosynthesis represent promising targets for the development of novel antibacterial drugs. Here, the crystal structure of Mycobacterium bovis MurC (MbMurC) is reported, which exhibits a three-domain architecture for the binding of UNAM, ATP and an amino acid as substrates, with a nickel ion at the domain interface. The ATP-binding loop adopts a conformation that is not seen in other MurCs. In the UNAG-bound structure of MbMurC, the substrate mimic interacts with the UDP-binding domain of MbMurC, which does not invoke rearrangement of the three domains. Interestingly, the glycine-rich loop of the UDP-binding domain of MbMurC interacts through hydrogen bonds with the glucose moiety of the ligand, but not with the pyrophosphate moiety. These findings suggest that UNAG analogs might serve as potential candidates for neutralizing the catalytic activity of bacterial MurC.

Bioerodible polyanhydrides for antibiotic drug delivery: In vivo osteomyelitis treatment in a rat model system

1993 ◽  
Vol 11 (2) ◽  
pp. 256-262 ◽  
Author(s):  
C. T. Laurencin ◽  
T. Gerhart ◽  
P. Witschger ◽  
R. Satcher ◽  
A. Domb ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Rat Model ◽  
Model System ◽  
Antibiotic Drug

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

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