Structural insights into the psychrophilic germinal protease PaGPR and its autoinhibitory loop.

In spore forming microbes, germination protease (GPR) plays a key role in the initiation of the germination process. A critical step during germination is the degradation of small acid-soluble proteins (SASPs), which protect spore DNA from external stresses (UV, heat, low temperature, etc.). Inactive zymogen GPR can be activated by autoprocessing of the N-terminal pro-sequence domain. Activated GPR initiates the degradation of SASPs; however, the detailed mechanisms underlying the activation, catalysis, regulation, and substrate recognition of GPR remain elusive. In this study, we determined the crystal structure of GPR from Paenisporosarcina sp. TG-20 (PaGPR) in its inactive form at a resolution of 2.5 A. Structural analysis showed that the active site of PaGPR is sterically occluded by an inhibitory loop region (residues 202-216). The N-terminal region interacts directly with the self-inhibitory loop region, suggesting that the removal of the N-terminal pro-sequence induces conformational changes, which lead to the release of the self-inhibitory loop region from the active site. In addition, comparative sequence and structural analyses revealed that PaGPR contains two highly conserved Asp residues (D123 and D182) in the active site, similar to the putative aspartic acid protease GPR from Bacillus megaterium. The catalytic domain structure of PaGPR also shares similarities with the sequentially non-homologous proteins HycI and HybD. HycI and HybD are metal-loproteases that also contain two Asp (or Glu) residues in their active site, playing a role in metal binding. In summary, our results provide useful insights into the activation process of PaGPR and its active conformation.

Exploring the Pharmacological Potentials of Biosurfactant Derived from Planococcus maritimus SAMP MCC 3013.

Therapeutic potential of biosurfactant (BS) has been improved in recent years. Our present study deals with production of BS from Planococcus maritimus SAMP MCC 3013 in a mineral salt medium (MSM) supplemented with glucose (1.5% w/v). Further, BS has been purified and partially characterized as glycolipid type through our previous publication. Current research article aimed to evaluate biological potential of BS against Mycobacterium tuberculosis, Plasmodium falciparum and cancerous cell lines. Planococcus derived glycolipid BS was found to be a promising inhibitor of M. tuberculosis (MTB) H37Ra at IC50 64.11 ± 1.64 µg/mL and MIC at 160.8 ± 1.64 µg/mL. BS also showed growth inhibition of P. falciparum at EC50 34.56 ± 0.26 µM. Additionally, BS also displayed the cytotoxicity against HeLa (IC50 41.41 ± 4.21 µg/mL), MCF-7 (IC50 42.79 ± 6.07 µg/mL) and HCT (IC50 31.233 ± 5.08 µg/mL) cell lines. Molecular docking analysis was carried for the most popular glycolipid type BS namely Rhamnolipid (RHL) aiming to interpret the possible binding interaction for anti-tubercular and anti-cancer activity. This analysis revealed the involvement of RHL binding with enoyl reductase (InhA) of M. tuberculosis. Docking studies of RHL with tubulin directed several hydrophobic and Vander Waal interactions to exhibit anti-cancer potential. The present study will be helpful for further development of marine bioactive molecules for therapeutic applications. Their anti-tubercular, anti-plasmodial and cytotoxic activities make BS molecules as a noteworthy candidate to combat several diseases. To the best of our knowledge, this is the first report on projecting the pharmacological potential of Planococcus derived BS.

Highly enantioselective resolution of racemic 1-phenyl-1,2-ethanediol to (S)-1-phenyl-1,2-ethanediol by Kurthia gibsonii SC0312 in a biphasic system.

The asymmetric resolution of racemic 1-phenyl-1,2-ethanediol (PED) to (S)-PED by Kurthia gibsonii SC0312 (K. gibsonii SC0312) was conducted in a biphasic system comprised of an organic solvent and aqueous phosphate buffer. The impacts of organic solvents on the whole cell catalytic activity, metabolic activity, membrane integrity, and material distribution were first evaluated. The results showed that all organic solvents, except for dibutyl phthalate, showed a detrimental effect on the metabolic activity of the cells, especially for those with low log P values. All organic solvents were capable of changing the membrane permeability and membrane integrity of the cells. Moreover, some organic solvents showed a good extraction of the oxidation product. Finally, a high yield of 47.7 % of (S)-PED was obtained by the asymmetric resolution of racemic PED using K. gibsonii SC0312 in a biphasic system under the optimal conditions: racemic PED 120 mM, temperature 35 °C, reaction time 6 h, 180 rpm, and a volume ratio of dibutyl phthalate to aqueous phosphate buffer of 1:1. The optical purity of (S)-PED increased from 51.3 % to >99 %. This work described an efficient approach to improve reaction efficiency, and constructed a highly effective biphasic reaction system for the fabrication of (S)-PED via K. gibsonii SC0312.

Genome sequence of the Antarctic psychrophile bacterium Planococcus antarcticus DSM 14505.

Planococcus antarcticus DSM 14505 is a psychrophile bacterium that was isolated from cyanobacterial mat samples, originally collected from ponds in McMurdo, Antarctica. This orange-pigmented bacterium grows at 4°C and may possess interesting enzymatic activities at low temperatures. Here we report the first genomic sequence of P. antarcticus DSM 14505.

The draft genome of Planococcus donghaensis MPA1U2 reveals nonsporulation pathways controlled by a conserved Spo0A regulon.

The Planococcaceae are extreme survivors, having been cultured from environments such as deep sea sediments, marine solar salterns, glaciers, permafrost, Antarctic deserts, and sea ice brine. The family contains both sporulating and nonsporulating genera. Here we present the unclosed, draft genome sequence of Planococcus donghaensis strain MPA1U2, a nonsporulating psychrotrophic bacterium isolated from surface coastal water of the Pacific Ocean.