Structure and cleavage pattern of a hyaluronate 3-glycanohydrolase in the glycoside hydrolase 79 family.

Hyaluronidases have attracted a great deal of interest in the field of medicine due to their fundamental roles in the breakdown of hyaluronan. However, little is known about the catalytic mechanism of the hyaluronate 3-glycanohydrolases. Here, we report the crystal structure and cleavage pattern of a leech hyaluronidase (LHyal), which hydrolyzes the ß-1,3-glycosidic bonds of hyaluronan. LHyal exhibits the typical structural features of glycoside hydrolase 79 family but contains a variable 'exo-pocket' loop where basic residues R102 and K103 are the structural determinants of hyaluronan binding. Through analysis of the hydrolysis of even- and odd-numbered hyaluronan oligosaccharides, we demonstrate that hexasaccharide is the shortest natural substrate, which can be cleaved from both the reducing and non-reducing ends to release disaccharides, and pentasaccharides are the smallest fragments for recognition and hydrolysis. These observations provide new insights into the degradation of hyaluronan and the evolutionary relationships of the GH79 family enzymes.

Temperature-controlled molecular weight of hyaluronic acid produced by engineered Bacillus subtilis.

To produce high-, medium- and low-molecular-weight hyaluronic acid (HA) at different temperatures using engineered Bacillus subtilis expressing hyaluronidase (HAase) from leech. By overexpressing the HAase gene hya in the HA-producing strain WmB using temperature-sensitive plasmid pKSV7, the engineered strain WmB-PYh produced HA with different molecular weights (8.61 kDa at 32 °C, 0.615 MDa at 42 °C, and 6.19 MDa at 47 °C). In this study, the molecular weight of HA was regulated by using leech HAase expressed from a temperature-sensitive plasmid. We thus obtained different molecular weight HAs by using a single bacterial strain at different culture temperatures.

Purification and characterization of a novel fibrinolytic enzyme from Whitmania pigra Whitman.

Developing an effective fibrinolytic drug for treating thrombolysis with minimal undesirable side effects is of great importance. In the current study, an optimum solvent was selected for the extraction of fibrinolytic active components. Furthermore, a strong fibrinolytic enzyme named WPI01 was purified from Whitmania pigra Whitman through various chromatographic steps. WPI01 has a molecular mass of 27044.297 Da, and the N-terminal 8 amino acid sequence was determined as VVGGVEAR. WPI01 was stable within the pH range of 6.0-10.0 and with maximum fibrinolytic activity at 40 °C and a pH of 8.0. At 500 U/mL, WPI01 induced 50.59% blood clot reduction in vitro within 6 h, which was higher than that induced by urokinase at 1000 U/mL. In an analysis of the plasminogen activator activity, WPI01 produced obvious halos on heated and unheated fibrin plates, suggesting that WPI01 may not only act as a plasminogen activator but also degrade fibrin clots directly, and more study is needed to support this. In conclusion, WPI01 is obviously different from known fibrinolytic enzymes in terms of substrate specificity and fibrinolytic mode of action, suggesting that it is a novel fibrinolytic enzyme with potential applications in the treatment and prevention of thrombosis.

Characterization of a monoacylglycerol lipase in the medicinal leech, Hirudo verbana.

Endocannabinoids are a class of lipid neuromodulators found throughout the animal kingdom. Among the endocannabinoids, 2-arachydonoyl glycerol (2-AG) is the most prevalent endocannabinoid and monoacylglycerol lipase (MAGL) is a serine hydrolase primarily responsible for metabolizing 2-AG in mammals. In the medicinal leech, Hirudo verbana, 2-AG has been found to be an important and multi-functional modulator of synaptic transmission and behavior. However, very little is known about the molecular components of its synthesis and degradation. In this study we have identified cDNA in Hirudo that encodes a putative MAGL (HirMAGL). The encoded protein exhibits considerable sequence and structural conservation with mammalian forms of MAGL, especially in the catalytic triad that mediates 2-AG metabolism. Additionally, HirMAGL transcripts are detected in the Hirudo central nervous system. When expressed in HEK 293 cells HirMAGL segregates to the plasma membrane as expected. It also exhibits serine hydrolase activity that is blocked when a critical active site residue is mutated. HirMAGL also demonstrates the capacity to metabolize 2-AG and this capacity is also prevented when the active site is mutated. Finally, HirMAGL activity is inhibited by JZL184 and MJN110, specific inhibitors of mammalian MAGL. To our knowledge these findings represent the first characterization of an invertebrate form of MAGL and show that HirMAGL exhibits many of the same properties as mammalian MAGL's that are responsible for 2-AG metabolism.

High-level constitutive expression of leech hyaluronidase with combined strategies in recombinant Pichia pastoris.

Hyaluronidases that break down hyaluronan are widely used for preparation of low molecular weight hyaluronan. Leech hyaluronidase (LHyal) is a newly discovered hyaluronidase with outstanding enzymatic properties. The Pichia pastoris expression system of LHyal that depends on AOX1 promoter (PAOX1) has been constructed. However, the addition of the toxic inducer methanol is a big safety concern. Here, a combinational strategy was adopted for constitutive expression of LHyal to high level in P. pastoris. By optimizing the combination of promoters PGAP, PGAP(m), and PTEF1 and signal peptides α-factor, nsB, and sp23, the enzyme activity of extracellular LHyal reached 1.38 × 105 U/mL in shake flasks. N-terminal engineering with neutral polar amino acids further increased LHyal activity to 2.06 × 105 U/mL. In addition, the impact of overexpressing transcription factors Aft1, Gal4-like, and Yap1 on LHyal production was also investigated. We found the co-expression of Aft1 significantly enhanced the expression of LHyal to 3.03 × 105 U/mL. Finally, LHyal activity of 2.12 × 106 U/mL was achieved in a 3-L fermenter, with a high productivity of 1.96 × 104 U/mL/h. The engineered LHyal-producing Pichia pastoris strains will be more attractive for production of hyaluronidase on industrial scale.

Marine Leech Anticoagulant Diversity and Evolution.

Leeches (Annelida: Hirudinea) possess powerful salivary anticoagulants and, accordingly, are frequently employed in modern, authoritative medicine. Members of the almost exclusively marine family Piscicolidae account for 20% of leech species diversity, and they feed on host groups (e.g., sharks) not encountered by their freshwater and terrestrial counterparts. Moreover, some species of Ozobranchidae feed on endangered marine turtles and have been implicated as potential vectors for the tumor-associated turtle herpesvirus. In spite of their ecological importance and unique host associations, there is a distinct paucity of data regarding the salivary transcriptomes of either of these families. Using next-generation sequencing, we profiled transcribed, putative anticoagulants and other salivary bioactive compounds that have previously been linked to blood feeding from 7 piscicolid species (3 elasmobranch feeders; 4 non-cartilaginous fish feeders) and 1 ozobranchid species (2 samples). In total, 149 putative anticoagulants and bioactive loci were discovered in varying constellations throughout the different samples. The putative anticoagulants showed a broad spectrum of described antagonistic pathways, such as inhibition of factor Xa and platelet aggregation, which likely have similar bioactive roles in marine fish and turtles. A transcript with homology to ohanin, originally isolated from king cobras, was found in Cystobranchus vividus but is otherwise unknown from leeches. Estimation of selection pressures for the putative anticoagulants recovered evidence for both positive and purifying selection along several isolated branches in the gene trees, and positive selection was also estimated for a few select codons in a variety of marine species. Similarly, phylogenetic analyses of the amino acid sequences for several anticoagulants indicated divergent evolution.

Whitmania Pigra Whitman Extracts Inhibit Lipopolysaccharide Induced Rat Vascular Smooth Muscle Cells Migration and their Adhesion Ability to THP-1 and RAW 264.7 Cells.

AIM: Atherosclerosis is a kind of chronic inflammatory disease. A crucial pathology change of atherosclerosis is the migration of activated VSMCs to the intima where they interact with leukocytes by expressing adhesion molecules, including intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Moreover, monocyte chemoattractant protein-1 (MCP-1) expressed by VSMCs plays an important role in recruiting monocytes and macrophages. Leech (Whitmania pigra Whitman) is a traditional Chinese medicine to treat cardiovascular diseases including atherosclerosis, however previous research has rarely reported the molecular mechanism for its curative effect. Thus, our study focuses on the effects of leech extracts on the expression of inflammatory factors, adhesion molecules and MCP-1 in rat VSMCs. METHODS: In our present study, wound-healing assay and Boyden chamber model were applied to evaluate the anti-migration effect of LEE (Leech Enzyme Extracts) on LPS induced VSMCs. The anti-adhesion effect was assessed using DiI-labeled THP-1 and RAW264.7. RESULTS: LEE suppressed LPS-induced VSMCs migration and decreased the chemotaxis and adhesive capacity of THP-1 and RAW264.7 to LPS-stimulated VSMCs. LEE also attenuated the upregulation of a variety of pro-atherosclerotic factors by inhibiting the phosphorylation of p38 MAPK. LEE was also observed to prevent NF-κB p65 nuclear localization using immune-fluorescent staining. CONCLUSIONS: In conclusion, LEE suppresses LPS-induced upregulation of inflammatory factors, adhesion molecules and MCP-1 in rat VSMCs mainly via inhibiting the p38 MAPK/NF-κB pathways, thus partly uncovered LEE's molecular mechanisms for its therapeutic effect on atherosclerosis.

Purification and characterization of a novel fibrinolytic enzyme from Whitmania pigra Whitman.

A fibrinolytic enzyme was purified from the dry body of Whitmania pigra Whitman. The fibrinolytic enzyme was purified to homogeneity with a yield of 0.003% and a purification of 630.7 fold. The molecular weight of the enzyme was estimated to be 26.7 kDa by reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was tested by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and it showed that the enzyme was a novel fibrinolytic enzyme. The optimal pH and temperature of the enzyme were 8.5 and 55°C, respectively. Enzyme activity was enhanced by Na+, Mg2+, and K+. On the contrary, the proteolytic activity was significantly inhibited by Mn2+, Fe2+, Fe3+, ethylenediaminetetraacetic acid (EDTA), and ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA). Fibrinolytic and fibrinogenolytic assays showed that the enzyme preferentially hydrolyzed fibrinogen Aα-chains, followed by Bß- and γ-chains. The α-, ß-, and γ-γ-chains of fibrin were also degraded by the enzyme.

Characterisation of separated end hyaluronan oligosaccharides from leech hyaluronidase and evaluation of angiogenesis.

Hyaluronan oligosaccharides (o-HAs), especially saturated o-HAs, have attracted intensive attention due to their potential applications in medical treatments. In this study, the hydrolysis process of leech hyaluronidase (LHase) towards the hyaluronan was investigated by HPLC and HPLC/ESI-MS. The proportions of hyaluronan tetrasaccharide (HA4) with hexasaccharide (HA6), end products, were illustrated to have a relationship with the amount of LHase. Higher yield of HA4 was achieved with higher activity of LHase. After optimisation of the packing resin and operation parameters (balanced pH, elution concentration, elution volume and elution flow rate), the highly pure HA4 and HA6 were efficiently separated and prepared by combining ion exchange Q-Sepharose Fast Flow and size exclusion column chromatography. Compared with o-HAs (average Mr of 4000 Da), HA4 and HA6 were demonstrated to show higher activity for promoting angiogenesis, which was similar with the corresponding HA4 and HA6 produced by bovine testicular hyaluronidase. The pure HA4 and HA6 that prepared from LHase will attract intensive studies and be used in potential applications in near future.

Production of specific-molecular-weight hyaluronan by metabolically engineered Bacillus subtilis 168.

Low-molecular-weight hyaluronan (LMW-HA) has attracted much attention because of its many potential applications. Here, we efficiently produced specific LMW-HAs from sucrose in Bacillus subtilis. By coexpressing the identified committed genes (tuaD, gtaB, glmU, glmM, and glmS) and downregulating the glycolytic pathway, HA production was significantly increased from 1.01gL(-1) to 3.16gL(-1), with a molecular weight range of 1.40×10(6)-1.83×10(6)Da. When leech hyaluronidase was actively expressed after N-terminal engineering (1.62×10(6)UmL(-1)), the production of HA was substantially increased from 5.96gL(-1) to 19.38gL(-1). The level of hyaluronidase was rationally regulated with a ribosome-binding site engineering strategy, allowing the production of LMW-HAs with a molecular weight range of 2.20×10(3)-1.42×10(6)Da. Our results confirm that this strategy for the controllable expression of hyaluronidase, together with the optimization of the HA synthetic pathway, effectively produces specific LMW-HAs, and could also be used to produce other LMW polysaccharides.

Combinatorial Evolution of Enzymes and Synthetic Pathways Using One-Step PCR.

DNA engineering is the fundamental motive driving the rapid development of modern biotechnology. Here, we present a versatile evolution method termed "rapidly efficient combinatorial oligonucleotides for directed evolution" (RECODE) for rapidly introducing multiple combinatorial mutations to the target DNA by combined action of a thermostable high-fidelity DNA polymerase and a thermostable DNA Ligase in one reaction system. By applying this method, we rapidly constructed a variant library of the rpoS promoters (with activity of 8-460%), generated a novel heparinase from the highly specific leech hyaluronidase (with more than 30 mutant residues) and optimized the heme biosynthetic pathway by combinatorial evolution of regulatory elements and pathway enzymes (2500 ± 120 mg L(-1) with 20-fold increase). The simple RECODE method enabled researchers the unparalleled ability to efficiently create diverse mutant libraries for rapid evolution and optimization of enzymes and synthetic pathways.

[Effects of stocking density and exchanging water frequency on growth and inner quality of Whitmania pigra].

The effects of stocking density and exchanging water frequency on growth, digestive enzyme activity, anti-oxidative enzyme and inner quality of Whitmania pigra Whitman were evaluated with corresponding measures. The results showed that the eventual biomass, specific growth rate, gained weight rate, activities of amylase, lipase, protease, SOD, CAT, and ALP correlated positively with stocking density and negatively with exchanging water frequency (P<0.05). Exchanging water frequency had negative correlation with ammonia nitrogen, nitrite, and hydrogen sulfide while revealed positive correlation with dissolved oxygen in the water. Stocking density and exchanging water frequency showed no significant effects on the contents of moisture, total ash, and acid-insoluble ash. It suggested that the optimum stocking density was 7.5 million per hectare and the appropriate exchanging water interval was 72 h.

Enhanced production of leech hyaluronidase by optimizing secretion and cultivation in Pichia pastoris.

Leech hyaluronidase (LHAase) was recently cloned and successfully expressed in Pichia pastoris. To increase its secretory expression level, four signal peptides (nsB, YTP1, SCS3, and HKR1) and six amphipathic peptides (APs) were comparatively investigated. After substitution with nsB and fusion with AP2, the production of LHAase was significantly increased, from 8.42 × 10(5) to 1.24 × 10(6) U/ml. Compared with the parental LHAase, the variant AP2-LHAase showed a lower optimum pH (5.0), higher optimum temperature (50 °C), and a broader range of thermal stability (20-60 °C). To further promote fermentative production of the variant AP2-LHAase, the cultivation temperature was systematically optimized according to cell viability and alcohol oxidase activity. Eventually, through a combination of N-terminal engineering and optimization of cultivation, the production of LHAase was improved to 1.68 × 10(6) U/ml, with a high productivity of 1.87 × 10(4) U/ml/h.

[Studies on digestive enzyme activity of Whitmania pigra in different months old].

Studies on the variation of amylase, lipase and lrotease activity of Whitmania pigra in 0-6 months old using 3, 5-dinitro- salicylic acid colorimetry, right-nitrophenyl palmitate ester (ρ-NPP) colorimetry and folin-phenol method. The results showed that pro- tease activity remained low before 1.5 months old and with the highest activity in 2 months old, but after showing a small peak in 4 months, alkaline protease rapid declined. Amylase was low at born, then gradually increased the activity of the highest in 2.5 months old. Lipase with a strong vitality at birth, then 1 month with minimum and 2 months peaked, but appeared a small peak in 4 months old. In summary, only lipase exhibits strong activity at birth, lipase with the strongest activity in the digestive tract during develop- ment. Protease, lipase and amylase with the strongest activity at 2-3 months old, but were decreased after 4 months old.

Enzymatic production of specifically distributed hyaluronan oligosaccharides.

High-molecular-mass hyaluronan (HA) was controllably depolymerized in pure aqueous solution with recombinant leech hyaluronidase (HAase). The HAase concentration per unit HA and hydrolysis time played important roles in molecular mass distribution. By modulating the concentrations of HAase and controlling the hydrolysis time, any molar-mass-defined HA oligomers could be efficiently and specifically produced on a large scale (40 g/L), such as HA oligosaccharides with weight-average molar mass of 4000, 10,000, and 30,000Da and end hydrolysates containing only HA6 and HA4. High performance liquid chromatography-size exclusion chromatography, polyacrylamide gel electrophoresis, capillary zone electrophoresis, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry confirmed low polydispersity of the produced molar-mass-defined HA oligosaccharides. Therefore, large-scale production of defined HA oligosaccharides with narrow molecular mass distribution will significantly promote progress in related research and its potential applications.

High-yield novel leech hyaluronidase to expedite the preparation of specific hyaluronan oligomers.

Hyaluronidases (HAases), particularly leech HAases, have attracted intense attention due to their broad applications in medical treatments and great potential for the enzymatic production of hyaluronan oligosaccharides. However, little is known about this third interesting family of HAases. Here, we applied the random amplification of cDNA ends polymerase chain reaction (RACE-PCR) approach to identify the first leech HAase-encoding gene. By combining protein engineering and high-density culture, we achieved high-level production (8.42 × 10(5) U ml(-1)) in the yeast Pichia pastoris secretory expression system. Compared with the commercial bovine testicular HAase, the recombinant leech HAase exhibited superior enzymatic properties. Furthermore, analysis of the hydrolytic process suggested that this novel enzyme adopts a nonprocessive endolytic mode, yielding a narrow-spectrum of specific HA oligosaccharides with different incubation times. Large-scale production of this novel leech HAase will not only greatly promote medical applications but also facilitate the enzymatic production of specific HA oligosaccharides.

[Effects of temperature and pH on digestive enzymes activities in Whitmania pigra].

OBJECTIVE: Current study was conducted to investigate and compare the impact of temperature and pH on the activities of amylase, protease and lipase in alimentary tract of Whitmania pigra. METHOD: The responses of amylase, protease, and lipase activities were determined over a wide range of temperatures (7-52 degrees C) and pH gradient (2.2-11.2). RESULT: The highest lipase activity was found under 37 degrees C, pH 8.2, and the highest amylase activity was detected under 37 degrees C, pH 5.2, while protease activity peaked at 42 degrees C, pH 3.2 or pH 9.2. CONCLUSION: The optimal temperature in alimentary tract of Wh. pigra for lipase and amylase was 37 degrees C, and the responding temperature for protease was 42 degrees C. The optimal pH value in alimentary tract of Wh. pigra for lipase and amylase was pH 8.2 and pH 5.2, respectively. While pH 3.2 or 9.2 seems to be both favorable for high protease activity.

[Lysozyme activity of the salivary gland secretion of the medicinal leech H. verbana, H. medicinalis and H. orientalis].

Salivary gland secretions of three species of the medicinal leech differ in the level of lysozyme peptidoglycan-lysing activity. Using the synthetic fluorogenic substrate, 4-methyl-umbelliferyl tetra N-acetyl-beta-chitotetraosid, the glycosidase activity (as one of peptidoglycan-lysing activities) of salivary gland secretion of three species of the medicinal leech was quantitatively evaluated in comparison with egg lysozyme. It is supposed, that lysozyme activity of the leech secretions is determined not only by 5 isoforms of destabilase-lysozyme, but by some other enzymes which can utilize this substrate. These may be lysozymes other than i- (invertebrate) lysozymes (such as destabilase-lysozyme, or related enzymes).

Destabilase-lysozyme of medicinal leech. Multifunctionality of recombinant protein.

Preparation and purification of a recombinant protein are described along with characteristics of its specific (for ε-(γ-Glu)-Lys and D-dimer substrates) and nonspecific (for L-γ-Glu-pNA) isopeptidase activities; the absence of peptidase function for α-(α-Glu)-Lys substrate is noted. It is shown that the protein exhibits muramidase (cell walls of Micrococcus lysodeikticus) and specific glycosidase activities. The latter was determined towards the fluorogenic substrate 4-methylumbelliferyl-tetra-N-acetyl-ß-chitotetraoxide. Antimicrobial activity of recombinant destabilase-lysozyme protein (recDest-Lys) and its 11-membered amphipathic peptide was revealed towards cells of the strict anaerobic Archaean Methanosarcina barkeri, whose cell walls contain no murein. Possible mechanisms of the effect of recDest-Lys on these cells are discussed.

DNA barcoding reveals Mexican diversity within the freshwater leech genus Helobdella (Annelida: Glossiphoniidae).

We investigated the genetic distances and taxonomic status among species of Helobdella, a genus of non-blood-feeding leeches, based on mitochondrial cytochrome c oxidase subunit I sequences. Sampling included 20 specimens representing nine nominal species collected in 11 states in Mexico as well as previously published sequences of different species of Helobdella from several places. A neighbor-joining tree, as well as identification of diagnostic nucleotides, was used to suggest the presence of seven species of Helobdella in Mexico including potentially two undescribed forms.