Serological characteristics of ABO blood group and molecular genetic analysis of a Chinese pedigree with cisAB09 subtype / 中华医学遗传学杂志

OBJECTIVE@#To explore the serological characteristics of ABO blood group and molecular genetic mechanism for a Chinese pedigree with cisAB09 subtype.@*METHODS@#A pedigree undergoing ABO blood group examination at the Department of Transfusion, Zhongshan Hospital Affiliated to Xiamen University on February 2, 2022 was selected as the study subjects. Serological assay was carried out to determine the ABO blood group of the proband and his family members. Activities of A and B glycosyltransferases in the plasma of the proband and his mother were measured with an enzymatic assay. Expression of A and B antigens on the red blood cells of the proband was analyzed by flow cytometry. Peripheral blood samples of the proband and his family members were collected. Following extraction of genomic DNA, exons 1 to 7 of the ABO gene and their flanking introns were sequenced, and Sanger sequencing of exon 7 was carried out for the proband, his elder daughter and mother.@*RESULTS@#The results of serological assay suggested that the proband and his elder daughter and mother had an A2B phenotype, whilst his wife and younger daughter had an O phenotype. Measurement of plasma A and B glycosyltransferase activity suggested that the titers of B-glycosyltransferase activity were 32 and 256 for the proband and his mother, which were respectively below and above that of A1B phenotype-positive controls (128). Flow cytometry analysis showed that the expression of A antigen on the red blood cell surface of the proband has decreased, whilst the expression of B antigen was normal. Genetic sequencing confirmed that, in addition to an ABO*B.01 allele, the proband, his elder daughter and mother have harbored a c.796A>G variant in exon 7, which has resulted in substitution of the methionine at 266th position of the B-glycosyltransferase by valine and conformed to the characteristics of ABO*cisAB.09 allele. The genotypes of the proband and his elder daughter were determined as ABO*cisAB.09/ABO*O.01.01, his mother was ABO*cisAB.09/ABO*B.01, and his wife and younger daughter were ABO*O.01.01/ABO*O.01.01.@*CONCLUSION@#The c.796A>G variant of the ABO*B.01 allele has resulted in an amino acid substitution p.Met266Val, which probably underlay the cisAB09 subtype. The ABO*cisA B.09 allele encodes a special glycosyltransferase which can synthesize normal level of B antigen and low level of A antigen on the red blood cells.

Gene clone and functional identification of sterol glycosyltransferases from Paris polyphylla var. yunnanensis / 中国中药杂志

In this study, the authors cloned a glycosyltransferase gene PpUGT2 from Paris polyphylla var. yunnanensis with the ORF length of 1 773 bp and encoding 590 amino acids. The phylogenetic tree revealed that PpUGT2 belonged to the UGT80A subfamily and was named as UGT80A49 by the UDP-glycosyltransferase(UGT) Nomenclature Committee. The expression vector pET28a-PpUGT2 was constructed, and enzyme catalytic reaction in vitro was conducted via inducing protein expression and extraction. With UDP-glucose as sugar donor and diosgenin and pennogenin as substrates, the protein was found with the ability to catalyze the C-3 hydroxyl β-glycosylation of diosgenin and pennogenin. To further explore its catalytic characteristic, 15 substrates including steroids and triterpenes were selected and PpUGT2 showed its activity towards the C-17 position of sterol testosterone with UDP-glucose as sugar donor. Homology modelling and molecule docking of PpUGT2 with substrates predicted the key residues interacting with ligands. The re-levant residues of PpUGT2-ligand binding model were scanned to calculate the corresponding mutants, and the optimized mutants were obtained according to the changes in binding affinity of the ligand with protein and the surrounding residues within 5.0 Å of ligands, which had reference value for design of the mutants. This study laid a foundation for further exploring the biosynthetic pathway of polyphyllin as well as the structure of sterol glycosyltransferases.

Functional characterization and enzymatic properties of flavonoid glycosyltransferase gene CtUGT49 in Carthamus tinctorius / 中国中药杂志

Carthami Flos, as a traditional blood-activating and stasis-resolving drug, possesses anti-tumor, anti-inflammatory, and immunomodulatory pharmacological activities. Flavonoid glycosides are the main bioactive components in Carthamus tinctorius. Glycosyltransferase deserves to be studied in depth as a downstream modification enzyme in the biosynthesis of active glycoside compounds. This study reported a flavonoid glycosyltransferase CtUGT49 from C. tinctorius based on the transcriptome data, followed by bioinformatic analysis and the investigation of enzymatic properties. The open reading frame(ORF) of the gene was 1 416 bp, encoding 471 amino acid residues with the molecular weight of about 52 kDa. Phylogenetic analysis showed that CtUGT49 belonged to the UGT73 family. According to in vitro enzymatic results, CtUGT49 could catalyze naringenin chalcone to the prunin and choerospondin, and catalyze phloretin to phlorizin and trilobatin, exhibiting good substrate versatility. After the recombinant protein CtUGT49 was obtained by hetero-logous expression and purification, the enzymatic properties of CtUGT49 catalyzing the formation of prunin from naringenin chalcone were investigated. The results showed that the optimal pH value for CtUGT49 catalysis was 7.0, the optimal temperature was 37 ℃, and the highest substrate conversion rate was achieved after 8 h of reaction. The results of enzymatic kinetic parameters showed that the K_m value was 209.90 μmol·L~(-1) and k_(cat) was 48.36 s~(-1) calculated with the method of Michaelis-Menten plot. The discovery of the novel glycosyltransferase CtUGT49 is important for enriching the library of glycosylation tool enzymes and provides a basis for analyzing the glycosylation process of flavonoid glycosides in C. tinctorius.

The glycosyltransferases involved in triterpenoid saponin biosynthesis: a review / 生物工程学报

Triterpenoid saponins are widely used in medicine, health cares, cosmetics, food additives and agriculture because of their unique chemical properties and rich pharmacological activities. UDP-dependent glycosyltransferases (UGTs) are the key enzymes involved in triterpenoid saponin biosynthesis, and play important roles in the diversity of triterpenoid saponin structures and pharmacological activities. This review summarized the UGTs involved in plant triterpenoid saponin biosynthesis based on the sources of UGTs and the types of receptors. Moreover, the application of UGTs in heterologous biosynthesis of triterpenoid saponins based on synthetic biology was also discussed.

Cloning and functional analysis of caffeic acid and rosmarinic acid glycosyltransferases from Arnebia euchroma / 中国中药杂志

Caffeic acid and its oligomers are the main water-soluble active constituents of the traditional Chinese medicine(TCM) Arnebiae Radix. These compounds possess multiple biological activities such as antimicrobial, antioxidant, cardiovascular protective, liver protective, anti-liver fibrosis, antiviral and anticancer activities. The phenylpropanoid pathway in plants is responsible for the biosynthesis of caffeic acid and its oligomers. Glycosylation can change phenylpropanoid solubility, stability and toxic potential, as well as influencing compartmentalization and biological activity. In view of the important role played by de-glycosylation in the regulation of phenylpropanoid homeostasis, the biosynthesis of caffeic acid and its oligomers are supposed to be under the control of relative UDP-glycosyltransferases(UGTs). Through the data mining of Arnebia euchroma transcriptome, we cloned 15 full-length putative UGT genes. After recombinant expression using the prokaryotic system, the crude enzyme solution of the putative UGTs was examined for the glycosylation activities towards caffeic acid and rosmarinic acid in vitro. AeUGT_01, AeUGT_02, AeUGT_03, AeUGT_04 and AeUGT_10 were able to glycosylate caffeic acid and/or rosmarinic acid resulting in different mono-and/or di-glycosylated products in the UPLC-MS analyses. The characterized UGTs were distantly related to each other and divided into different clades of the phylogenetic tree. Based on the observation that each characterized UGT exhibited substrate or catalytic similarity with the members in their own clade, we supposed the glycosylation abilities towards caffeic acid and/or rosmarinic acid were evolved independently in different clades. The identification of caffeic acid and rosmarinic acid UGTs from A. euchroma could lead to deeper understanding of the caffeic acid oligomers biosynthesis and its regulation. Furthermore, these UGTs might be used for regiospecific glycosylation of caffeic acid and rosmarinic acid to produce bioactive compounds for potential therapeutic applications.

Application of sucrose phosphorylase in glycosylation / 生物工程学报

Water solubility, stability, and bioavailability, can be substantially improved after glycosylation. Glycosylation of bioactive compounds catalyzed by glycoside hydrolases (GHs) and glycosyltransferases (GTs) has become a research hotspot. Thanks to their rich sources and use of cheap glycosyl donors, GHs are advantageous in terms of scaled catalysis compared to GTs. Among GHs, sucrose phosphorylase has attracted extensive attentions in chemical engineering due to its prominent glycosylation activity as well as its acceptor promiscuity. This paper reviews the structure, catalytic characteristics, and directional redesign of sucrose phosphorylase. Meanwhile, glycosylation of diverse chemicals with sucrose phosphorylase and its coupling applications with other biocatalysts are summarized. Future research directions were also discussed based on the current research progress combined with our working experience.

Identification of a glycosyltransferase allele associated with Bw subtype and analysis of the protein structure / 中华医学遗传学杂志

OBJECTIVE@#To explore the molecular basis for an individual with Bw subtype.@*METHODS@#Routine serological reactions were used to determine the surface antigens of erythrocytes and antibodies in serum. PCR-sequence-based typing (PCR-SBT) was used to analyze the coding regions of the ABO gene and erythroid-specific regulatory element in its intron 1. Amplicons for exons 5 to 7 containing the variant site were subjected to TA cloning for the isolation of the haploid and verification of the sequence. The 3D structure of mutant protein was predicted with Pymol software. Changes of amino acid residues and structural stability were also analyzed.@*RESULTS@#Serological assay showed that the individual had weakened B antigen and anti-B antibody in his serum. His genotype was determined as ABO*B.01/ABO*O.01.01. Sequencing of the entire coding region of the ABO gene identified an additional heterozygous c.734C/T variant. No variant was found in the erythroid-specific regulatory element of intron 1. Haploid cloning and isolation has obtained an ABO*O.01.01 allele and a ABO*B.01 allele containing a c.734T variant, which has led to substitution of Thr by Ile at position 245 in the functional center of glycosyltransferase. Based on the 3D structure of the protein, the residues binding with the mutation were unchanged, but the bonding distance between the hydrogens was changed with the amino acid substitution. Meanwhile, the connections with water molecules were increased.@*CONCLUSION@#The c.734C>T variant of the GTB gene can lead to an amino acid substitution in the functional center of the enzyme, which in turn may affect the stability of glycosyltransferase B protein and reduceits enzymatic activity.

Transcriptional Regulation of Proteoglycans and Glycosaminoglycan Chain-synthesizing Glycosyltransferases by UV Irradiation in Cultured Human Dermal Fibroblasts

Various kinds of glycosaminoglycans (GAGs) and proteoglycans (PGs) have been known to be involved in structural and space-filling functions, as well as many physiological regulations in skin. To investigate ultraviolet (UV) radiation-mediated regulation of GAGs and PGs in cultured human dermal fibroblasts, transcriptional changes of many types of PGs and GAG chain-synthesizing enzymes at 18 hr after 75 mJ/cm2 of UV irradiation were examined using quantitative real-time polymerase chain reaction methods. Hyaluronic acid synthase (HAS)-1, -2, and -3 and hyaluronidase-2 mRNA expressions were significantly increased by UV irradiation. Expressions of lumican, fibromodulin, osteoglycin, syndecan-2, perlecan, agrin, versican, decorin, and biglycan were significantly decreased by UV irradiation, while syndecan-1 was increased. Expressions of GAG chain-synthesizing glycosyltransferases, xylosyltransferase-1, beta1,3-glucuronyltransferase-1, beta1,4-galactosyltransferase-2, -4, exostosin-1, chondroitin polymerizing factor, and chondroitin sulfate synthase-3 were significantly reduced, whereas those of beta1,3-galactosyltransferase-6, beta1,4-galactosyltransferase-3, -7, beta-1,3-N-acetylglucosaminyltran sferase-2, and -7 were increased by UV irradiation. Heparanase-1 mRNA expression was increased, but that of heparanase-2 was reduced by UV irradiation. Time-course investigation of representative genes showed consistent results. In conclusion, UV irradiation may increase hyaluronic acid production through HAS induction, and decrease other GAG productions through downregulation of PG core proteins and GAG chain-synthesizing glycosyltransferases in cultured human dermal fibroblasts.

Identification of a root-specific glycosyltransferase from Arabidopsis and characterization of its promoter.

A set of Ds-element enhancer trap lines of Arabidopsis thaliana was generated and screened for expression patterns leading to the identification of a line that showed root-specific expression of the bacterial uidA reporter gene encoding beta-glucuronidase (GUS). The insertion of the Ds element was found to be immediately downstream to a glycosyltransferase gene At1g73160. Analysis of At1g73160 expression showed that it is highly root-specific. Isolation and characterization of the upstream region of the At1g73160 gene led to the definition of a 218 bp fragment that is sufficient to confer root-specific expression. Sequence analysis revealed that several regulatory elements were implicated in expression in root tissue. The promoter identified and characterized in this study has the potential to be applied in crop biotechnology for directing the root-specific expression of transgenes.

Isolation and expression of the genes coding for the membrane bound transglycosylase B (MltB) and the transferrin binding protein B (TbpB) of the salmon pathogen Piscirickettsia salmonis

We have isolated and sequenced the genes encoding the membrane bound transglycosylase B (MltB) and the transferring binding protein B (TbpB) of the salmon pathogen Piscirickettsia salmonis. The results of the sequence revealed two open reading frames that encode proteins with calculated molecular weights of 38,830 and 85,140. The deduced aminoacid sequences of both proteins show a significant homology to the respective protein from phylogenetically related microorganisms. Partial sequences coding the amino and carboxyl regions of MltB and a sequence of 761 base pairs encoding the amino region of TbpB have been expressed in E. coli. The strong humoral response elicited by these proteins in mouse confirmed the immunogenic properties of the recombinant proteins. A similar response was elicited by both proteins when injected intraperitoneally in Atlantic salmon. The present data indicates that these proteins are good candidates to be used in formulations to study the protective immunity of salmon to infection by P. salmonis.

Genetic engineering and dental caries.

Dental caries, a multifactorial disease requires four principle factor: the host, the microflora, the substrate & time for its occurrence and can be prevented or managed by elimination/modification of either of the above factors. The conventional preventive measure being followed for long time for the dental caries are not successful to the desirable extent due to their non avaibailaballity in the rural areas, lack of awareness & inaccessibility of dental services. Therefore, the focus has now been shifted to submicroscopic level to ensure that these measures can be reached to the farthest areas & each & every member of the population is benefitted. Few of the measures taken are. i) Genetically modifying the S. Mutans: ii) Searching The antagonist peptides to work against the specific enzyme system (Glucosyltransferase) of S. Mutans. iii) Changing the oral environment by those Genetically modified organisms that will produce bases (instead of acids) & these bases provides a milieu favoring remineralization. This paper discusses various ways in which genetically modified strains of microogranisms or genetically modified strains of microogranisms of genetically modified foods can help in the prevention of caries.