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At least 19 recordsLinked to original sources
PubMed2001

Profiling serine hydrolase activities in complex proteomes.

Serine hydrolases represent one of the largest and most diverse families of enzymes in higher eukaryotes, comprising numerous proteases, lipases, esterases, and amidases. The activities of many serine hydrolases are tightly regulated by posttranslational mechanisms, limiting the suitability of standard genomics and proteomics methods for the functional characterization of these enzymes. To facilitate the global analysis of serine hydrolase activities in complex proteomes, a biotinylated fluorophosphonate (FP-biotin) was recently synthesized and shown to serve as an activity-based probe for several members of this enzyme family. However, the extent to which FP-biotin reacts with the complete repertoire of active serine hydrolases present in a given proteome remains largely unexplored. Herein, we describe the synthesis and utility of a variant of FP-biotin in which the agent's hydrophobic alkyl chain linker was replaced by a more hydrophilic poly(ethylene glycol) moiety (FP-peg-biotin). When incubated with both soluble and membrane proteomes for extended reaction times, FP-biotin and FP-peg-biotin generated similar "maximal coverage" serine hydrolase activity profiles. However, kinetic analyses revealed that several serine hydrolases reacted at different rates with each FP agent. These rate differences were exploited in studies that used the biotinylated FPs to examine the target selectivity of reversible serine hydrolase inhibitors directly in complex proteomes. Finally, a general method for the avidin-based affinity isolation of FP-biotinylated proteins was developed, permitting the rapid and simultaneous identification of multiple serine peptidases, lipases, and esterases. Collectively, these studies demonstrate that chemical probes such as the biotinylated FPs can greatly accelerate both the functional characterization and molecular identification of active enzymes in complex proteomes.

Animals↗
PubMed2003

Synergistic computational and experimental proteomics approaches for more accurate detection of active serine hydrolases in yeast.

An analysis of the structurally and catalytically diverse serine hydrolase protein family in the Saccharomyces cerevisiae proteome was undertaken using two independent but complementary, large-scale approaches. The first approach is based on computational analysis of serine hydrolase active site structures; the second utilizes the chemical reactivity of the serine hydrolase active site in complex mixtures. These proteomics approaches share the ability to fractionate the complex proteome into functional subsets. Each method identified a significant number of sequences, but 15 proteins were identified by both methods. Eight of these were unannotated in the Saccharomyces Genome Database at the time of this study and are thus novel serine hydrolase identifications. Three of the previously uncharacterized proteins are members of a eukaryotic serine hydrolase family, designated as Fsh (family of serine hydrolase), identified here for the first time. OVCA2, a potential human tumor suppressor, and DYR-SCHPO, a dihydrofolate reductase from Schizosaccharomyces pombe, are members of this family. Comparing the combined results to results of other proteomic methods showed that only four of the 15 proteins were identified in a recent large-scale, "shotgun" proteomic analysis and eight were identified using a related, but similar, approach (neither identifies function). Only 10 of the 15 were annotated using alternate motif-based computational tools. The results demonstrate the precision derived from combining complementary, function-based approaches to extract biological information from complex proteomes. The chemical proteomics technology indicates that a functional protein is being expressed in the cell, while the computational proteomics technology adds details about the specific type of function and residue that is likely being labeled. The combination of synergistic methods facilitates analysis, enriches true positive results, and increases confidence in novel identifications. This work also highlights the risks inherent in annotation transfer and the use of scoring functions for determination of correct annotations.

Amino Acid Sequence↗
PubMed2005

Serine hydrolase targets of organophosphorus toxicants.

Acetylcholinesterase (AChE) is one of several hundred serine hydrolases in people potentially exposed to about 80 organophosphorus (OP) compounds important as insecticides or chemical warfare agents. The toxicology of OPs was interpreted until recently almost solely on the basis of AChE inhibition. It is assumed that each serine hydrolase has a specific function and proposed that every OP compound has a unique inhibitory profile. This review considers the progress in sifting the expanding list of potential serine hydrolase toxicological targets. About 50 serine hydrolase targets have been recognized but only a few studied thoroughly. The toxicological relevance of known secondary OP targets is established mainly from observations with humans (butyrylcholinesterase and neuropathy target esterase-lysophospholipase) and studies with mice (cannabinoid CB1 receptor, carboxylesterase, lysophospholipase and platelet activating factor acetylhydrolase) and hen eggs (arylformamidase or kynurenine formamidase). Pesticides most commonly shown to inhibit these targets in experimental vertebrates are chlorpyrifos and tribufos. Generally the levels of environmental and occupational OP pesticide exposure are well below those causing in vivo inhibition of secondary serine hydrolase targets. Although exposure to OP insecticides is decreasing from stricter regulations and the development of resistant pest strains, it will continue to some degree for decades in the future. Only two OPs are used as pharmaceuticals, i.e. echothiophate as an ophthalmic for treatment of glaucoma and metrifonate as an anthelmintic for Schistosoma (and formerly as a candidate drug for improved cognitive function in Alzheimer's disease). In safety evaluations, knowledge on known OP targets must be balanced against major gaps in current understanding since more than 75% of the serine hydrolases are essentially unknown as to OP targeting and relevance, i.e. it is not clear if they play a role in OP toxicology.

Animals↗
PubMed1999

Bacterial 2,4-dioxygenases: new members of the alpha/beta hydrolase-fold superfamily of enzymes functionally related to serine hydrolases.

1H-3-hydroxy-4-oxoquinoline 2,4-dioxygenase (Qdo) from Pseudomonas putida 33/1 and 1H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase (Hod) from Arthrobacter ilicis Rü61a catalyze an N-heterocyclic-ring cleavage reaction, generating N-formylanthranilate and N-acetylanthranilate, respectively, and carbon monoxide. Amino acid sequence comparisons between Qdo, Hod, and a number of proteins belonging to the alpha/beta hydrolase-fold superfamily of enzymes and analysis of the similarity between the predicted secondary structures of the 2,4-dioxygenases and the known secondary structure of haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 strongly suggested that Qdo and Hod are structurally related to the alpha/beta hydrolase-fold enzymes. The residues S95 and H244 of Qdo were found to be arranged like the catalytic nucleophilic residue and the catalytic histidine, respectively, of the alpha/beta hydrolase-fold enzymes. Investigation of the potential functional significance of these and other residues of Qdo through site-directed mutagenesis supported the hypothesis that Qdo is structurally as well as functionally related to serine hydrolases, with S95 being a possible catalytic nucleophile and H244 being a possible catalytic base. A hypothetical reaction mechanism for Qdo-catalyzed 2,4-dioxygenolysis, involving formation of an ester bond between the catalytic serine residue and the carbonyl carbon of the substrate and subsequent dioxygenolysis of the covalently bound anionic intermediate, is discussed.

Amino Acid Sequence↗
PubMed2003

Chlorophyllase as a serine hydrolase: identification of a putative catalytic triad.

Chlorophyllases (Chlases), cloned so far, contain a lipase motif with the active serine residue of the catalytic triad of triglyceride lipases. Inhibitors specific for the catalytic serine residue in serine hydrolases, which include lipases effectively inhibited the activity of the recombinant Chenopodium album Chlase (CaCLH). From this evidence we assumed that the catalytic mechanism of hydrolysis by Chlase might be similar to those of serine hydrolases that have a catalytic triad composed of serine, histidine and aspartic acid in their active site. Thus, we introduced mutations into the putative catalytic residue (Ser162) and conserved amino acid residues (histidine, aspartic acid and cysteine) to generate recombinant CaCLH mutants. The three amino acid residues (Ser162, Asp191 and His262) essential for Chlase activity were identified. These results indicate that Chlase is a serine hydrolase and, by analogy with a plausible catalytic mechanism of serine hydrolases, we proposed a mechanism for hydrolysis catalyzed by Chlase.

Amino Acid Sequence↗
PubMed1995

Cloning and expression analysis of a novel human serine hydrolase with sequence similarity to prokaryotic enzymes involved in the degradation of aromatic compounds.

A full-length cDNA coding for a novel human serine hydrolase has been cloned from a breast carcinoma cDNA library. Nucleotide sequence analysis has shown that the isolated cDNA contains an open reading frame coding for a polypeptide of 274 amino acids and a complete Alu repetitive sequence within its 3'-untranslated region. The predicted amino acid sequence contains the Gly-X-Ser-X-Gly motif characteristic of serine hydrolases and displays extensive similarity to several prokaryotic hydrolases involved in the degradation of aromatic compounds. The highest degree of identities was detected with four serine hydrolases encoded by the bphD genes of different strains of Pseudomonas with the ability to degrade biphenyl derivatives. On the basis of these sequence similarities, this novel human enzyme has been tentatively called Biphenyl hydrolase-related protein (Bph-rp). The Bph-rp cDNA was expressed in Escherichia coli, and after purification, the recombinant protein was able to degrade p-nitrophenylbutyrate, a water-soluble substrate commonly used for assaying serine hydrolases. This hydrolytic activity was abolished by diisopropyl fluorophosphate, a covalent inhibitor of serine hydrolases, providing additional evidence that the isolated cDNA encodes a member of this protein superfamily. Northern blot analysis of poly(A)+ RNAs isolated from a variety of human tissues revealed that Bph-rp is mainly expressed in liver and kidney, which was also confirmed at the protein level by Western blot analysis with antibodies raised against purified recombinant Bph-rp. According to structural characteristics, hydrolytic activity and tissue distribution of Bph-rp, a potential role of this enzyme in detoxification processes is proposed.

Amino Acid Sequence↗
PubMed1981

Glucocorticoid regulation of two serine hydrolases in rat splenic lymphocytes in vitro.

A quantitative assay employing binding of [3H] diisopropylfluorophosphate ([3H]DFP) and SDS-polyacrylamide gel electrophoresis was used to measure serine hydrolases in cell-free extracts from rat splenic lymphocytes. After labeling with [3H]DFP at pH7, six major serine hydrolases are detected on 10% gels, having molecular weights of 78, 55, 34, 30, 28, and 17 (.10(-3)). When labeled at pH4, only four activities are measured, with Mr of 79, 55, 33 and 17(.10(-3)). Incubation of splenic lymphocytes for 8 h in vitro with 1 microM dexamethasone followed by [3H]-DFP labeling at pH 7 produces a 91% increase in the 17000 [3H]DFP. Hormone treatment for 8 h with subsequent labeling at pH 4 results in a 15% increase in the largest (78000) species, as well as 73% increase in the 17000 enzyme, compared with lysates from cells incubated without steroid. These effects are not observed after only 4 h of glucocorticoid exposure. Dexamethasone treatment for 8 h does not produce a decrease in any of these serine hydrolases, nor is there an apparent induction of new enzymes (i.e., having a molecular weight different from the preexisting species). Studies examining the effect of protease inhibitors on the [3H]DFP capacity of these proteins, show that the 17000 enzyme is sensitive to the protease inhibitor, pepstatin A, as well as the sulfhydryl reagents dithiothreitol and N-ethylmaleimide. These results suggest that this dexamethasone-responsive enzyme is a protease which requires a free thiol group for optimal activity. These findings are discussed with regard to the mechanism of glucocorticoid action in lymphocytes.

Animals↗
PubMed1999

Chemical and mutagenic investigations of fatty acid amide hydrolase: evidence for a family of serine hydrolases with distinct catalytic properties.

Fatty acid amide hydrolase (FAAH) is a membrane-bound enzyme responsible for the catabolism of neuromodulatory fatty acid amides, including anandamide and oleamide. FAAH's primary structure identifies this enzyme as a member of a diverse group of alkyl amidases, known collectively as the "amidase signature family". At present, this enzyme family's catalytic mechanism remains poorly understood. In this study, we investigated the catalytic features of FAAH through mutagenesis, affinity labeling, and steady-state kinetic methods. In particular, we focused on the respective roles of three serine residues that are conserved in all amidase signature enzymes (S217, S218, and S241 in FAAH). Mutation of each of these serines to alanine resulted in a FAAH enzyme bearing significant catalytic defects, with the S217A and S218A mutants showing 2300- and 95-fold reductions in k(cat), respectively, and the S241A mutant exhibiting no detectable catalytic activity. The double S217A:S218A FAAH mutant displayed a 230 000-fold decrease in k(cat), supporting independent catalytic functions for these serine residues. Affinity labeling of FAAH with a specific nucleophile reactive inhibitor, ethoxy oleoyl fluorophosphonate, identified S241 as the enzyme's catalytic nucleophile. The pH dependence of FAAH's k(cat) and k(cat)/K(m) implicated a base involved in catalysis with a pK(a) of 7.9. Interestingly, mutation of each of FAAH's conserved histidines (H184, H358, and H449) generated active enzymes, indicating that FAAH does not contain a Ser-His-Asp catalytic triad commonly found in other mammalian serine hydrolytic enzymes. The unusual properties of FAAH identified here suggest that this enzyme, and possibly the amidase signature family as a whole, may hydrolyze amides by a novel catalytic mechanism.

Affinity Labels↗
PubMed1994

(His)C epsilon-H...O=C < hydrogen bond in the active sites of serine hydrolases.

Close interactions of the C-H...O type are known to occur in a variety of organic crystals, although it had been often argued that they do not represent true hydrogen bonds. During an extensive comparative study of all structurally characterized serine hydrolases containing an Asp(Glu)-His-Ser catalytic triad at their active centers (i.e. serine proteinases, lipases, acetylcholinesterase and a thioesterase), we have discovered that the C epsilon 1 atom of the active site histidine is invariably in a close contact with a carbonyl oxygen. The stereochemistry of these contacts suggests a cohesive, predominantly electrostatic interaction, fully consistent with the requirements imposed by the generally accepted definition of a hydrogen bond. A study of a sample of protein structures refined at high resolution revealed that similar hydrogen bonds involving (His) C epsilon 1-H are found in approximately 15% of non-active site histidine residues. The ubiquitous occurrence of this hitherto underestimated contact in the active sites of serine hydrolases suggests functional significance. We propose that the (His)C epsilon 1-H...O=C bond affects the charge distribution within the imidazolium ion so as to weaken the N epsilon 2-H bond, thereby facilitating general acid catalysis by the active site histidine during both the acylation and deacylation steps of hydrolysis.

Acetylcholinesterase↗
PubMed2005

Crystal structure of yeast YHR049W/FSH1, a member of the serine hydrolase family.

Yhr049w/FSH1 was recently identified in a combined computational and experimental proteomics analysis for the detection of active serine hydrolases in yeast. This analysis suggested that FSH1 might be a serine-type hydrolase belonging to the broad functional alphabeta-hydrolase superfamily. In order to get insight into the molecular function of this gene, it was targeted in our yeast structural genomics project. The crystal structure of the protein confirms that it contains a Ser/His/Asp catalytic triad that is part of a minimal alpha/beta-hydrolase fold. The architecture of the putative active site and analogies with other protein structures suggest that FSH1 may be an esterase. This finding was further strengthened by the unexpected presence of a compound covalently bound to the catalytic serine in the active site. Apparently, the enzyme was trapped with a reactive compound during the purification process.

Amino Acid Sequence↗
PubMed2004

Identify catalytic triads of serine hydrolases by support vector machines.

The core of an enzyme molecule is its active site from the viewpoints of both academic research and industrial application. To reveal the structural and functional mechanism of an enzyme, one needs to know its active site; to conduct structure-based drug design by regulating the function of an enzyme, one needs to know the active site and its microenvironment as well. Given the atomic coordinates of an enzyme molecule, how can we predict its active site? To tackle such a problem, a distance group approach was proposed and the support vector machine algorithm applied to predict the catalytic triad of serine hydrolase family. The success rate by jackknife test for the 139 serine hydrolases was 85%, implying that the method is quite promising and may become a useful tool in structural bioinformatics.

Algorithms↗
PubMed1999

Activity-based protein profiling: the serine hydrolases.

With the postgenome era rapidly approaching, new strategies for the functional analysis of proteins are needed. To date, proteomics efforts have primarily been confined to recording variations in protein level rather than activity. The ability to profile classes of proteins on the basis of changes in their activity would greatly accelerate both the assignment of protein function and the identification of potential pharmaceutical targets. Here, we describe the chemical synthesis and utility of an active-site directed probe for visualizing dynamics in the expression and function of an entire enzyme family, the serine hydrolases. By reacting this probe, a biotinylated fluorophosphonate referred to as FP-biotin, with crude tissue extracts, we quickly and with high sensitivity detect numerous serine hydrolases, many of which display tissue-restricted patterns of expression. Additionally, we show that FP-biotin labels these proteins in an activity-dependent manner that can be followed kinetically, offering a powerful means to monitor dynamics simultaneously in both protein function and expression.

Animals↗
PubMed1997

Functional expression of a tobacco gene related to the serine hydrolase family -- esterase activity towards short-chain dinitrophenyl acylesters.

We have recently reported the isolation of a tobacco gene, hsr 203J, whose transcripts accumulate during the hypersensitive reaction, a plant response associated with resistance to pathogens. We present and discuss here some structural and biochemical properties of the gene product. Nucleotide sequence analysis has shown that the hsr 203J gene contains an open reading frame coding for a polypeptide of 335 amino acids. The predicted amino acid sequence contains the GXSXG motif characteristic of serine hydrolases, and displays limited but significant similarity to lipases and esterases of prokaryotic origin. The hsr 203J gene was expressed in Escherichia coli, and the recombinant protein, purified to near homogeneity, was able to degrade p-nitrophenylbutyrate, a general substrate for carboxylesterases. The enzyme was unable to hydrolyze lipids, and was active on short-chain acyl esters only. The hydrolytic activity was abolished by diisopropyl fluorophosphate and a derivative of isocoumarin, as expected for a member of the serine hydrolase family. Sequence similarities between the tobacco esterase and expressed sequence tags in databases suggest the existence of members of this enzyme family in various plant species.

Butyrates↗
PubMed2006

Serine hydrolase KIAA1363: toxicological and structural features with emphasis on organophosphate interactions.

Serine hydrolase KIAA1363 is highly expressed in invasive cancer cells and is the major protein in mouse brain diethylphosphorylated by and hydrolyzing low levels of chlorpyrifos oxon (CPO) (the activated metabolite of a major insecticide). It is also the primary CPO-hydrolyzing enzyme in spinal cord, kidney, heart, lung, testis, and muscle but not liver, a pattern of tissue expression confirmed by fluorophosphonate-rhodamine labeling. KIAA1363 gene deletion using homologous recombination reduces CPO binding, hydrolysis, and metabolism 3-29-fold on incubation with brain membranes and homogenates determined with 1 nM [(3)H-ethyl]CPO and the inhibitory potency for residual CPO with butyrylcholinesterase as a biomarker. Studies with knockout mice further show that KIAA1363 partially protects brain AChE and monoacylglycerol lipase from CPO-induced in vivo inhibition. Surprisingly, mouse brain KIAA1363 and AChE are similar in in vitro sensitivity to seven methyl, ethyl, and propyl but not higher alkyl OP insecticides and analogues, prompting structural comparisons of the active sites of KIAA1363 and AChE relative to OP potency and selectivity. Homology modeling based largely on the Archaeoglobus fulgidus esterase crystal structure indicates that KIAA1363 has a catalytic triad of S191, D348, and H378, a GDSAG motif, and an oxyanion hole of H113, G114, G115, and G116. Excellent selectivity for KIAA1363 is achieved on OP structure optimization with long alkyl chain substituents suggesting that KIAA1363 has larger acyl and leaving group pockets than those of AChE. KIAA1363 reactivates faster than AChE presumably due to differences in the uncoupling of the catalytic triad His upon phosphorylation. The structural modeling of KIAA1363 helps us understand OP structure-activity relationships and the toxicological relevance of this detoxifying enzyme.

Animals↗
PubMed2001

Identification of Serhl, a new member of the serine hydrolase family induced by passive stretch of skeletal muscle in vivo.

In response to extended periods of stretch, skeletal muscle typically exhibits cell hypertrophy associated with sustained increases in mRNA and protein synthesis. Several soluble hypertrophic agonists have been identified, yet relatively little is known as to how mechanical load is converted into intracellular signals regulating gene expression or how increased cell size is maintained. In skeletal muscle, hypertrophy is generally regarded as a beneficial adaptive response to increased workload. In some cases, however, hypertrophy can be detrimental as seen in long-term cardiac hypertrophy. Skeletal muscle wasting (atrophy) is a feature of both inherited and acquired muscle disease and normal aging. Elucidating the molecular regulation of cell size is a fundamental step toward comprehending the complex molecular systems underlying muscle hypertrophy and atrophy. Subtractive hybridization between passively stretched and control murine skeletal muscle tissue identified an mRNA that undergoes increased expression in response to passive stretch. Encoded within the mRNA is an open reading frame of 311 amino acids containing a highly conserved type 1 peroxisomal targeting signal and a serine lipase active center. The sequence shows identity to a family of serine hydrolases and thus is named serine hydrolase-like (Serhl). The predicted three-dimensional structure displays a core alpha/beta-hydrolase fold and catalytic triad characteristic of several hydrolytic enzymes. Endogenous Serhl protein immunolocalizes to perinuclear vesicles as does Serhl-FLAG fusion protein transiently expressed in muscle cells in vitro. Overexpression of Serhl-FLAG has no effect on muscle cell phenotype in vitro. Serhl's expression patterns and its response to passive stretch suggest that it may play a role in normal peroxisome function and skeletal muscle growth in response to mechanical stimuli.

Amino Acid Sequence↗
PubMed2005

Mass spectrometric identification of serine hydrolase OVCA2 in the medulloblastoma cell line DAOY.

OVCA2 is a putative serine-hydrolase. Performing protein profiling in human tumour cell lines, OVCA2 was detected in DAOY medulloblastoma cells as a high abundance protein. The protein was unambiguously identified by 2D gel-electrophoresis and MALDI-MS and MS/MS, its presence was confirmed by western blotting. Immunohistochemistry revealed expression in medulloblastoma and predominantly in oligodendrocytes. Computational approaches predicted functional motifs and domains, interaction with apoptosis-related protein BAG and 3D structure. In addition to the presence of OVCA2 in medulloblastoma, it was furthermore detectable in three out of 10 human tumour cell-lines as a high abundance protein probably suggesting a role in the tumour biology.

Amino Acid Sequence↗
PubMed2006

The putative endocannabinoid transport blocker LY2183240 is a potent inhibitor of FAAH and several other brain serine hydrolases.

How lipid transmitters move within and between cells to communicate signals remains an important and largely unanswered question. Integral membrane transporters, soluble lipid-binding proteins, and metabolic enzymes have all been proposed to collaboratively regulate lipid signaling dynamics in vivo. Assignment of the relative contributions made by each of these classes of proteins requires selective pharmacological agents to perturb their individual functions. Recently, LY2183240, a heterocyclic urea inhibitor of the putative endocannabinoid (EC) transporter, was shown to disrupt the cellular uptake of the lipid EC anandamide and promote analgesia in vivo. Here, we show that LY2183240 is a potent, covalent inhibitor of the EC-degrading enzyme fatty acid amide hydrolase (FAAH). LY2183240 inactivates FAAH by carbamylation of the enzyme's serine nucleophile. More global screens using activity-based proteomic probes identified several additional serine hydrolases that are also inhibited by LY2183240. These results indicate that the blockade of anandamide uptake observed with LY2183240 may be due primarily to the inactivation of FAAH, providing further evidence that this enzyme serves as a metabolic driving force that promotes the diffusion of anandamide into cells. More generally, the proteome-wide target promiscuity of LY2183240 designates the heterocyclic urea as a chemotype with potentially excessive protein reactivity for drug design.

Amidohydrolases↗
PubMed2006

Probing structure-function relationships of serine hydrolases and proteases with carbamate and thiocarbamate inhibitors.

Benzene-1,3-di-N-n-octylcarbamate (1), benzene-1-hydroxyl-3-N-n-octylcarbamate (2), benzene-1,3-di-N-n-ocztylthiocarbamate (3), and benzene-1-hydroxyl-3-N-n-octylthiocarbamate (4) are synthesized from 1,3-benzene-diol and are characterized as the pseudo-substrate inhibitors of acetylcholinesterase, butyrylcholinesterase, cholesterol esterase, lipase, trypsin, and chymotrypsin. For these six enzyme inhibitions by 1-4, the pKi values are linearly correlated with their log ki values - Brønsted plots. Therefore, 1-4 inhibit these enzymes through a common mechanism. Moreover, both pKi and log ki values for the inhibitions by 1,3, and 4 are linearly correlated with both pKi and log ki values for the inhibitions by 2, respectively. Thus, the pKi values for the inhibitions by 2 are defined as the nucleophilicity constants of these enzymes (nenzyme). The log k2 values for the inhibitions by 1-4 are also linearly correlated with the nenzyme values. Therefore, the nucleophilicity for serine hydrolases and proteases toward 1-4 also applies the Swain-Scott correlations.

Animals↗