The mechanism of action of primary alkylsulphohydrolase and arylsulphohydrolase from a detergent-degrading micro-organism.
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ABSTRACT:
SUBMITTER: Cloves JM
PROVIDER: S-EPMC1183735 | biostudies-other | 1977 Dec
REPOSITORIES: biostudies-other
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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:The P2 primary alkylsulphohydrolase of the soil bacterium Pseudomonas C12B was purified to homogeneity (200-250-fold) by column chromatography on DEAE-cellulose, Sephadex G-100 and butyl-agarose. The intact protein is a dimer with a mol. wt. of 160 000. Activity towards primary alkyl sulphate esters was maximal at pH 8.3, varied little in the range pH 7.8-8.7, but decreased sharply at higher pH. For a homologous series of primary alkyl sulphate substrates (C6-C12), logKm decreased linearly with increasing chain length, corresponding to a contribution to the free energy of association between enzyme and substrate of -2.5kJ/mol for each additional CH2 group in the alkyl chain. logKi for the competitive inhibition by secondary alkyl 2-sulphate esters followed a similar pattern (-2.4kJ/mol for each additional CH2 group) except that only n-1 carbon atoms effectively participate in hydrophobic bonding, implying that the C-1 methyl group is not involved. logKi values for inhibition primary alkanesulphonates also depended linearly on chain length but with a diminished gradient, indicating a free-energy increment of -1.2kJ/mol per additional CH2 group. The collective results showed the presence of a hydrophobic site on the enzyme capable of accomodating an alkyl chain of considerable length. Cationic structures (in the form of arginine, lysine or histidine), whose presence might be expected for binding the anionic sulphate group, were not detectable at the active site.
| S-EPMC1161265 | biostudies-other
Project description:Primary alkanesulphonates were shown to serve as non-metabolizable (gratuitous) inducers of the P2 primary alkylsulphohydrolase enzyme in resting cell suspensions of Pseudomonas C12B. The effects of increasing concentrations of inducer on the production of enzyme were complex and suggestive of a multiphasic phenomenon. However, it was possible to determine Kinducer constants (analogous to Km or Ki) for alkanesulphonates of chain length from C7 to c12. these decreased with increasing chain length in a manner characteristic of an homologous series. Primary alkyl sulphates also served as good inducers of alkylsulphohydrolase, but valid kinetic values could not be obtained because these esters are good substrates for the enzyme and are therefore appreciably hydrolysed during the induction period. Small amounts of enzyme were also produced when cyprinol sulphate, dodecyltriethoxy sulphate C12H23-[O-CH2-CH2]3-O-SO3-Na+), Crag herbicide and some secondary alkyl sulphates were tested as inducers.
| S-EPMC1161264 | biostudies-other
Project description:Isoeugenol is an essential oil constituent of nutmeg, clove, and cinnamon. Despite isoeugenol's promising antimicrobial activity, no studies have yet investigated its mode of antibacterial action at the molecular level. The aim of this study is to clarify isoeugenol's antibacterial mode of action using the Gram-negative and Gram-positive model organisms Escherichia coli and Listeria innocua, respectively. We determined the antimicrobial activity of isoeugenol against the model organisms, and examined how isoeugenol affects cell morphology, cell membrane permeabilization, and how isoeugenol interacts with phospholipid membranes using vesicle and supported lipid bilayer models. Isoeugenol demonstrated a bactericidal activity against E. coli and L. innocua that did not affect cell morphology, although the cell membrane was permeabilized. We hypothesized that the cell membrane was the primary site of action, and studied this interaction in further detail using purified membrane model systems. Isoeugenol's permeabilization of calcein-encapsulated vesicles was concentration dependent, and isoeugenol's interaction with giant unilamellar vesicles indicated increased membrane fluidity and a non-disruptive permeabilization mechanism. This contradicted membrane fluidity measurements on supported lipid bilayers (SLBs), which indicated decreased membrane fluidity. However, further investigations demonstrated that the interaction between isoeugenol and bilayers was reversible, and caused membranes to display heterogeneous topography, an increased mass, and a higher degree of hydration. In conclusion, we propose that isoeugenol interacts with membranes in a reversible non-disruptive detergent-like manner, which causes membrane destabilization. Furthermore, we argue that isoeugenol increases membrane fluidity. Our work contributes to the understanding of how essential oil constituents interact with cell components.
| S-EPMC4517379 | biostudies-literature
Project description:The inducible S3 secondary alkylsulphohydrolase of the soil bacterium Pseudomonas C12B was purified to homogeneity (683-fold from cell-free extracts by a combination of column chromatography on DEAE-cellulose. Sephadex G-100 and Blue Sepharose CL-6B. The enzyme has a molecular weight in the region of 40000--46000, and is active over a broad range of pH from 5 to 9, with maximum activity at pH 8.2. The preferred substrates of the enzyme are the symmetrical secondary alkylsulphate esters such as heptan-4-yl sulphate and nonan-5-yl sulphate and the asymmetric secondary octyl and nonyl sulphate esters with the sulphate group attached to C-3 or C-4. However, for each asymmetric ester, the L-isomer is much more readily hydrolysed than the D-isomer. This specificity is interpreted in terms of a three-point attachment of the substrate to the enzyme's active site. The alkyl chains on either side of the esterified carbon atom are bound in two separate sites, one of which can only accommodate alkyl chains of limited size. The third site binds the sulphate group. Enzymic hydrolysis of this group is accompanied by complete inversion of configuration at the asymmetric carbon atom. The implied cleavage of the C--O bond of the C--O--S ester linkage was confirmed by 18O-incorporation studies.
| S-EPMC1162506 | biostudies-other
Project description:The hydrolysis was studied of potassium (+)-octan-2-yl sulphate by two analogous, optically stereospecific, secondary alkylsulphohydrolases purified from two detergent-degrading micro-organisms, Comamonas terrigena and Pseudomonas C12B. Polarimetry studies have shown that (+)-octan-2-yl sulphate prepared from (+)-octan-2-ol is hydrolysed by both enzymes to yield (-)-octan-2-ol. This inversion of configuration implies that the enzymes are catalysing the scission of the C-O bond of the C-O-S linkage, a type of bond scission apparently not hitherto encountered among hydrolytic enzymes acting on ester bonds. Enzymic hydrolysis of potassium (+)-octan-2-yl sulphate in the presence of H218O and analysis of hydrolysis products for the presence of 18O has confirmed that C-O bond scission (and not O-S bond scission) occurs with both enzymes.
| S-EPMC1164941 | biostudies-other
Project description:Identification of methylase specificity in micro-organisms genomes
| PRJNA706563 | ENA
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:The P1 primary alkylsulphatase of Pseudomonas C12B was purified 1500-fold to homogeneity by a combination of streptomycin sulphate precipitation of nucleic acids, (NH4)2SO4 fractionation and chromatography on columns of DEAE-cellulose, Sephacryl S-300 and butyl-agarose. The protein was tetrameric with an Mr of 181000-193000, and exhibited maximum activity at pH 6.1. Primary alkyl sulphates of carbon-chain length C1-C5 or above C14 were not substrates, but the intermediate homologues were shown to be substrates, either by direct assay (C6-C9 and C12) or by gel zymography (C10, C11, C13 and C14). Increasing the chain length from C6 to C12 led to diminishing Km. Values of delta G0' for binding substrates to enzyme were dependent linearly on chain length, indicating high dependence on hydrophobic interactions. Vmax./Km values increased with increasing chain length. Inhibition by alk-2-yl sulphates and alkane-sulphonates was competitive and showed a similar dependence on hydrophobic binding. The P1 enzyme was active towards several aryl sulphates, including o-, m- and p-chlorophenyl sulphates, 2,4-dichlorophenyl sulphate, o-, m- and p-methoxyphenyl sulphates, m- and p-hydroxyphenyl sulphates and p-nitrophenyl sulphate, but excluding bis-(p-nitrophenyl) sulphate and the O-sulphate esters of tyrosine, nitrocatechol and phenol. The arylsulphatase activity was weak compared with alkylsulphatase activity, and it was distinguishable from the de-repressible arylsulphatase activity of Pseudomonas C12B reported previously. Comparison of the P1 enzyme with the inducible P2 alkylsulphatase of this organism, and with the Crag herbicide sulphatase of Pseudomonas putida, showed that, although there are certain similarities between any two of the three enzymes, very few properties are common to all three.
| S-EPMC1146854 | biostudies-other
Project description:MicroRNAs (miRNAs) are short, regulatory RNAs that act as post-transcriptional repressors of gene expression in diverse biological contexts. The emergence of small RNA-mediated gene silencing preceded the onset of multicellularity and was followed by a drastic expansion of the miRNA repertoire in conjunction with the evolution of complexity in the plant and animal kingdoms. Along this process, miRNAs became an essential feature of animal development, as no higher metazoan lineage tolerated loss of miRNAs or their associated protein machinery. In fact, ablation of the miRNA biogenesis machinery or the effector silencing factors results in severe embryogenesis defects in every animal studied. In this review, we summarize recent mechanistic insight into miRNA biogenesis and function, while emphasizing features that have enabled multicellular organisms to harness the potential of this broad class of repressors. We first discuss how different mechanisms of regulation of miRNA biogenesis are used, not only to generate spatio-temporal specificity of miRNA production within an animal, but also to achieve the necessary levels and dynamics of expression. We then explore how evolution of the mechanism for small RNA-mediated repression resulted in a diversity of silencing complexes that cause different molecular effects on their targets. Multicellular organisms have taken advantage of this variability in the outcome of miRNA-mediated repression, with differential use in particular cell types or even distinct subcellular compartments. Finally, we present an overview of how the animal miRNA repertoire has evolved and diversified, emphasizing the emergence of miRNA families and the biological implications of miRNA sequence diversification. Overall, focusing on selected animal models and through the lens of evolution, we highlight canonical mechanisms in miRNA biology and their variations, providing updated insight that will ultimately help us understand the contribution of miRNAs to the development and physiology of multicellular organisms.
| S-EPMC7283388 | biostudies-literature