Abstract:Proline utilization (Put) systems have been described in a number of bacteria; however, the importance and functionality of the Put system in the intracellular pathogen Brucellaabortus has not been explored. Generally, bacterial Put systems are composed of the bifunctional enzyme proline dehydrogenase PutA and its transcriptional activator PutR. Here, we demonstrate that the genes putA (bab2_0518) and putR (bab2_0517) are critical for the chronic infection of mice by B. abortus, but putA and putR are not requi… Show more
“…1B ) M2P media, showing that PutA is required for proline utilization by C. crescentus . This result strongly suggests that C. crescentus PutA can convert proline into glutamate as previously shown for PutA homologs from other Alphaproteobacteria 9 , 11 , 14 , 15 . Figure 1 PutA and PutR are required for proline utilization as a carbon source.…”
Section: Resultssupporting
confidence: 86%
“…Most bacteria use a bi-functional PutA enzyme to catabolize the conversion of proline into glutamate, the first step in proline utilization 3 . In order to study how C. crescentus uses proline as a source of nutrients, we searched for a putA homolog in its genome and found the CCNA_00846 protein that shares ~47% of identity with bi-functional PutA proteins from other Alphaproteobacteria 9 , 14 . It encodes a protein carrying two domains: one with similarities with the PRODH domain and the other one with similarities with the P5CDH domain, as expected for a bi-functional enzyme 3 .…”
Section: Resultsmentioning
confidence: 99%
“…In most but not all bacteria, both activities are carried by a single bi-functional enzyme called PutA 3 . This reaction is not only necessary for proline utilization, but also for a diversity of biological processes by bacteria such as infection, symbiosis and redox homeostasis 3 , 7 – 9 .…”
Section: Introductionmentioning
confidence: 99%
“…It is especially obvious in bacteria, where putA transcription is highly controlled by one or more transcription factors in response to nutrient availability 10 , 11 . In some bacteria, such as Escherichia coli or Salmonella thyphimurium , PutA has a DNA binding domain and can repress putA transcription 12 , 13 , while other bacteria, such as Agrobacterium tumefaciens or Brucella abortus encode an independent regulator named PutR to control putA transcription 9 , 14 . putA is sometimes regulated by PutA and PutR such as in Rhodobacter capsulatus 15 , illustrating the diversity of pathways regulating proline utilization in bacteria.…”
Cellular metabolism recently emerged as a central player modulating the bacterial cell cycle. The Alphaproteobacterium Caulobacter crescentus appears as one of the best models to study these connections, but its metabolism is still poorly characterized. Considering that it lives in oligotrophic environments, its capacity to use amino-acids is often critical for its growth. Here, we characterized the C. crescentus PutA bi-functional enzyme and showed that it is required for the utilization of proline as a carbon source. We also found that putA transcription and proline utilization by PutA are strictly dependent on the Lrp-like PutR activator. The activation of putA by PutR needs proline, which most likely acts as an effector molecule for PutR. Surprisingly, we also observed that an over-production of PutR leads to cell elongation in liquid medium containing proline, while it inhibits colony formation even in the absence of proline on solid medium. These cell division and growth defects were equally pronounced in a ΔputA mutant background, indicating that PutR can play other roles beyond the control of proline catabolism. Altogether, these findings suggest that PutR might connect central metabolism with cell cycle processes.
“…1B ) M2P media, showing that PutA is required for proline utilization by C. crescentus . This result strongly suggests that C. crescentus PutA can convert proline into glutamate as previously shown for PutA homologs from other Alphaproteobacteria 9 , 11 , 14 , 15 . Figure 1 PutA and PutR are required for proline utilization as a carbon source.…”
Section: Resultssupporting
confidence: 86%
“…Most bacteria use a bi-functional PutA enzyme to catabolize the conversion of proline into glutamate, the first step in proline utilization 3 . In order to study how C. crescentus uses proline as a source of nutrients, we searched for a putA homolog in its genome and found the CCNA_00846 protein that shares ~47% of identity with bi-functional PutA proteins from other Alphaproteobacteria 9 , 14 . It encodes a protein carrying two domains: one with similarities with the PRODH domain and the other one with similarities with the P5CDH domain, as expected for a bi-functional enzyme 3 .…”
Section: Resultsmentioning
confidence: 99%
“…In most but not all bacteria, both activities are carried by a single bi-functional enzyme called PutA 3 . This reaction is not only necessary for proline utilization, but also for a diversity of biological processes by bacteria such as infection, symbiosis and redox homeostasis 3 , 7 – 9 .…”
Section: Introductionmentioning
confidence: 99%
“…It is especially obvious in bacteria, where putA transcription is highly controlled by one or more transcription factors in response to nutrient availability 10 , 11 . In some bacteria, such as Escherichia coli or Salmonella thyphimurium , PutA has a DNA binding domain and can repress putA transcription 12 , 13 , while other bacteria, such as Agrobacterium tumefaciens or Brucella abortus encode an independent regulator named PutR to control putA transcription 9 , 14 . putA is sometimes regulated by PutA and PutR such as in Rhodobacter capsulatus 15 , illustrating the diversity of pathways regulating proline utilization in bacteria.…”
Cellular metabolism recently emerged as a central player modulating the bacterial cell cycle. The Alphaproteobacterium Caulobacter crescentus appears as one of the best models to study these connections, but its metabolism is still poorly characterized. Considering that it lives in oligotrophic environments, its capacity to use amino-acids is often critical for its growth. Here, we characterized the C. crescentus PutA bi-functional enzyme and showed that it is required for the utilization of proline as a carbon source. We also found that putA transcription and proline utilization by PutA are strictly dependent on the Lrp-like PutR activator. The activation of putA by PutR needs proline, which most likely acts as an effector molecule for PutR. Surprisingly, we also observed that an over-production of PutR leads to cell elongation in liquid medium containing proline, while it inhibits colony formation even in the absence of proline on solid medium. These cell division and growth defects were equally pronounced in a ΔputA mutant background, indicating that PutR can play other roles beyond the control of proline catabolism. Altogether, these findings suggest that PutR might connect central metabolism with cell cycle processes.
“…L‐Proline plays an important role in the virulence mechanism of various pathogens. Proline is the most hydrophilic amino acid and therefore it is found to accumulate in the cells of large variety of water‐stressed organisms and hence comes in the class of osmolytes . Proline used to stimulate the growth and respiration in bacteria in the presence of low water activities therefore act as proteogenic amino acid or “chaperone” to protein formation in the osmolytic conditions .…”
The structurally rigid dipeptide Pro‐Pro, known to self assembled into well defined dumbbells followed by robust three dimensional copper embedded discs under the appropriate physicochemical conditions. Now the assembly of dipeptide Pro‐Pro in the presence of Ag(I) and Au(III) metal ions was studied followed by its application as potential antibacterial agents. In the presence of Au(III) ions, ordered two dimensional sheets of submicron dimensions were obtained whereas in the presence of Ag(I) ions mostly random aggregates were found. Microscopy and spectroscopic study revealed that the Pro‐Pro‐Au(III) structures, in essence, can be considered as toxic metal ion “reservoirs“ and can provide batter platform to target bacterial membrane. The antibacterial assay demonstrated that owing to high biocompatibility Pro‐Pro dipeptide with bacterial cell, this simplest dipeptide worked as metal ion delivery agent and therefore it can show great potential in locally addressing bacterial infections.
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