A novel mechanism of enzymic ester hydrolysis. Inversion of configuration and carbon-oxygen bond cleavage by secondary alkylsulphohydrolases from detergent-degrading micro-organisms.
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ABSTRACT:
SUBMITTER: Bartholomew B
PROVIDER: S-EPMC1164941 | biostudies-other | 1977 Sep
REPOSITORIES: biostudies-other
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Project description:During the course of the purification of novel stereospecific secondary aklylsulphohydrolases present in certain detergent-degrading micro-organisms, it became apparent that substrates prepared by sulphating secondary alcohols with H2SO4 are heterogeneous. Apart from the racemization that occurs if resolved alcohols are sulphated, evidence is provided to show that other isomers are produced in which the position of the ester sulphate group on the alkyl chain has been altered. These changes can be avoided if pyridine/SO3 reagent (prepared with SO3) is substituted as sulphating agent. Experiments in which secondary alkyl sulphates prepared by both methods were tested as potential substrates for the two secondary alkylsulphohydrolase enzymes of Comamonas terrigena have provided initial information about the specificity of the enzymes.
| S-EPMC1183719 | biostudies-other
Project description:Petro-plastic wastes cause serious environmental contamination that require effective solutions. Developing alternatives to petro-plastics and exploring feasible degrading methods are two solving routes. Bio-plastics like polyhydroxyalkanoates (PHAs), polylactic acid (PLA), polycaprolactone (PCL), poly (butylene succinate) (PBS), poly (ethylene furanoate) s (PEFs) and poly (ethylene succinate) (PES) have emerged as promising alternatives. Meanwhile, biodegradation plays important roles in recycling plastics (e.g., bio-plastics PHAs, PLA, PCL, PBS, PEFs and PES) and petro-plastics poly (ethylene terephthalate) (PET) and plasticizers in plastics (e.g., phthalate esters, PAEs). All these bio- and petro-materials show structure similarity by connecting monomers through ester bond. Thus, this review focused on bio-plastics and summarized the sequences and structures of the microbial enzymes catalyzing ester-bond synthesis. Most of these synthetic enzymes belonged to α/β-hydrolases with conserved serine catalytic active site and catalyzed the polymerization of monomers by forming ester bond. For enzymatic plastic degradation, enzymes about PHAs, PBS, PCL, PEFs, PES and PET were discussed, and most of the enzymes also belonged to the α/β hydrolases with a catalytic active residue serine, and nucleophilically attacked the ester bond of substrate to generate the cleavage of plastic backbone. Enzymes hydrolysis of the representative plasticizer PAEs were divided into three types (I, II, and III). Type I enzymes hydrolyzed only one ester-bond of PAEs, type II enzymes catalyzed the ester-bond of mono-ester phthalates, and type III enzymes hydrolyzed di-ester bonds of PAEs. Divergences of catalytic mechanisms among these enzymes were still unclear. This review provided references for producing bio-plastics, and degrading or recycling of bio- and petro-plastics from an enzymatic point of view.
| S-EPMC9878459 | biostudies-literature
Project description:Previous studies have shown that secondary alkylsulphohydrolases from certain detergent-degrading micro-organisms are unusual esterases in that they catalyse fission of the C-O bond of the alkyl sulphate ester linkage. The position of bond fission catalysed by a primary alkylsulphatase and an arylsulphohydrolase present in Pseudomonas C12B has now been investigated. The primary alkylsulphatase behaved like the secondary alkylsulphohydrolases in cleaving the C-O bond of potassium heptan-1-yl sulphate. In contrast, the arylsulphohydrolase, in common with other similar enzymes previously studied, catalysed the fission of the O-S bond of potassium p-nitrophenyl sulphate.
| S-EPMC1183735 | biostudies-other
Project description:Methane production from hexadecene enrichment cultures
| PRJEB22123 | ENA
Project description:The S1 secondary alkylsulphohydrolase of the detergent-degrading micro-organism, Pseudomonas C12B, was separated from other alkylsulphohydrolases and purified to homogeneity. Under the experimental conditions used the enzyme completely hydrolysed d-octan-2-yl sulphate (d-1-methylheptyl sulphate), but showed no activity towards the corresponding l-isomer. Additional evidence has been obtained to indicate that it is probably optically stereospecific for d-secondary alkyl sulphate esters with the ester sulphate group at C-2 and with a chain length of at least seven carbon atoms. Enzyme activity towards racemic samples of heptan-2-yl sulphate (1-methylhexyl sulphate), octan-2-yl sulphate and decan-2-yl sulphate (1-methylnonyl sulphate) increased with increasing chain length. l-Octan-2-yl sulphate is a competitive inhibitor of the enzyme, as are certain primary alkyl sulphates and primary alkanesulphonates. Inhibition by each of the last two types of compounds is characteristic of the behaviour of an homologous series. Inhibition increases with increasing chain length and plots of log K(i) values against the number of carbon atoms in each alkyl chain show the expected linear relationship. A crude preparation of the S2 secondary alkylsulphohydrolase was used to show that this particular enzyme hydrolyses l-octan-2-yl sulphate, but is probably inactive towards the corresponding d-isomer. The similarity of the S1 and S2 enzymes to the CS2 and CS1 enzymes respectively of Comamonas terrigena was established, and some comments have been made on the possible roles of these and other alkylsulphohydrolases in the biodegradation of detergents.
| S-EPMC1183839 | biostudies-other
Project description:1. The action of cell-free filtrates from Trichoderma koningii was examined on undegraded cellulose in the form of cotton fibres, on degraded cellulose in the form of cellulose powder reprecipitated from phosphoric acid and on the soluble cellulose derivative CM-cellulose. 2. The cell-free filtrates compare favourably with intact cellulolytic micro-organisms in producing complete solubilization of undegraded as well as of degraded types of cellulose. Enzymic solubilization of cotton fibres gives quantitative conversion into glucose. Cellobiase is present. 3. The early enzymic breakdown of cotton fibres is characterized by the formation of very short fibres that increase to a maximum and disappear gradually by conversion into glucose. Disintegration of cotton fibres to short fibres is assisted by shaking, and within 20hr. the enzyme converts a minor fraction (up to 16%) of substrate into soluble products and a major portion (80%) into insoluble short fibres. 4. Maximum enzymic activity on cotton fibres occurs at about pH5.0, measured by the formation of short fibres, and at about pH3.8 on reprecipitated cellulose, measured by solubilization of the substrate. 5. Gluconolactone, glucose and cellobiose fail to produce marked inhibition of the enzymic hydrolysis of cotton fibres to short fibres or of the solubilization of reprecipitated cellulose unless present in amounts comparable with or greater than the initial weight of these two forms of cellulose. 6. The heavy-metal ions Cu(2+), Hg(2+) and Fe(3+) at 2mm concentration give 80-100% decrease in the enzymic breakdown of cotton fibres, measured by the formation of short fibres. At the same concentration Hg(2+) and Fe(3+) but not Cu(2+) also produce 70-100% inhibition of the solubilization of reprecipitated cellulose. 7. The ability to hydrolyse cotton fibres to short fibres and CM-cellulose to sugars is completely lost after heating enzyme preparations for 10min. at 71 degrees .
| S-EPMC1215204 | biostudies-other
Project description:When the time course of the hydrolysis of identical solutions of p-nitrophenyl N-acetyl-alpha-D-neuraminide by Salmonella typhimurium neuraminidase is monitored by u.v. and by its optical rotation, the rotation change is synchronous with, or even marginally in advance of, the absorbance change. In experiments under the same conditions with influenza-virus neuraminidase, known to react with retention of configuration [Chong, Pegg, Taylor and von Itzstein (1992) Eur. J. Biochem. 207, 335-343], the rotation change is much slower than the absorbance change. The inverting, presumably single-displacement, mode of action of the S. typhimurium enzyme follows from these observations, and the position (92.5% beta) of the slowly established mutarotational equilibrium of N-acetylneuraminic acid [Friebolin, Kunzelmann, Supp, Brossmer, Keilich and Ziegler (1981) Tetrahedron Lett. 22, 1383-1386].
| S-EPMC1137691 | biostudies-other
Project description:A number of simple oligopeptides have been recently developed as minimalistic catalysts for mimicking the activity and selectivity of natural proteases. Although the arrangement of amino acid residues in natural enzymes provides a strategy for designing artificial enzymes, creating catalysts with efficient binding and catalytic activity is still challenging. In this study, we used the polyproline scaffold and designed a series of 13-residue peptides with a catalytic dyad or triad incorporated to serve as artificial enzymes. Their catalytic efficiency on ester hydrolysis was evaluated by ultraviolet-visible spectroscopy using the p-nitrophenyl acetate assay, and their secondary structures were also characterized by circular dichroism spectroscopy. The results indicate that a well-formed polyproline II structure may result in a much higher catalytic efficiency. This is the first report to show that a functional dyad or triad engineered into a polyproline helix framework can enhance the catalytic activity on ester hydrolysis. Our study has also revealed the necessity of maintaining an ordered structure and a well-organized catalytic site for effective biocatalysts.
| S-EPMC6644415 | biostudies-literature
Project description:Glycoprotein B (gB) is the most highly conserved of the envelope glycoproteins of human herpesviruses. The gB protein of human cytomegalovirus (CMV) serves multiple roles in the life cycle of the virus. To investigate structural properties of gB that give rise to its function, we sought to determine the disulfide bond arrangement of gB. To this end, a recombinant form of gB (gB-S) comprising the entire ectodomain of the glycoprotein (amino acids 1 to 750) was constructed and expressed in insect cells. Proteolytic fragmentation and mass spectrometry were performed using purified gB-S, and the five disulfide bonds that link 10 of the 11 highly conserved cysteine residues of gB were mapped. These bonds are C94-C550, C111-C506, C246-C250, C344-C391, and C573-C610. This configuration closely parallels the disulfide bond configuration of herpes simplex type 2 (HSV-2) gB (N. Norais, D. Tang, S. Kaur, S. H. Chamberlain, F. R. Masiarz, R. L. Burke, and F. Markus, J. Virol. 70:7379-7387, 1996). However, despite the high degree of conservation of cysteine residues between CMV gB and HSV-2 gB, the disulfide bond arrangements of the two homologs are not identical. We detected a disulfide bond between the conserved cysteine residue 246 and the nonconserved cysteine residue 250 of CMV gB. We hypothesize that this disulfide bond stabilizes a tight loop in the amino-terminal fragment of CMV gB that does not exist in HSV-2 gB. We predicted that the cysteine residue not found in a disulfide bond of CMV gB, cysteine residue 185, would play a role in dimerization, but a cysteine substitution mutant in cysteine residue 185 showed no apparent defect in the ability to form dimers. These results indicate that gB oligomerization involves additional interactions other than a single disulfide bond. This work represents the second reported disulfide bond structure for a herpesvirus gB homolog, and the discovery that the two structures are not identical underscores the importance of empirically determining structures even for highly conserved proteins.
| S-EPMC136243 | biostudies-literature
Project description:Recent experiments with the bacteria Paenibacillus vortex reveal a remarkable strategy enabling it to cope with antibiotics by cooperating with a different bacterium-Escherichia coli. While P. vortex is a highly effective swarmer, it is sensitive to the antibiotic ampicillin. On the other hand, E. coli can degrade ampicillin but is non-motile when grown on high agar percentages. The two bacterial species form a shared colony in which E. coli is transported by P. vortex and E. coli detoxifies the ampicillin. The paper presents a simplified model, consisting of coupled reaction-diffusion equations, describing the development of ring patterns in the shared colony. Our results demonstrate some of the possible cooperative movement strategies bacteria utilize in order to survive harsh conditions. In addition, we explore the behavior of mixed colonies under new conditions such as antibiotic gradients, synchronization between colonies and possible dynamics of a 3-species system including P. vortex, E. coli and a carbon producing algae that provides nutrients under illuminated, nutrient poor conditions. The derived model was able to simulate an asymmetric relationship between two or three micro-organisms where cooperation is required for survival. Computationally, in order to avoid numerical artifacts due to symmetries within the discretizing grid, the model was solved using a second order Vectorizable Random Lattices method, which is developed as a finite volume scheme on a random grid.
| S-EPMC5746235 | biostudies-literature