Current concepts in ameloblastoma-targeted therapies in B-raf proto-oncogene serine/threonine kinase V600E mutation: Systematic review

BACKGROUND Ameloblastomas are common benign epithelial odontogenic neoplasms that present an aggressive and unpredictable behavior that may modify treatment strategies.Different signaling pathways that participate in the progression of these tumors have been identified.B-raf proto-oncogene serine/threonine kinase(BRAF)is a protein involved in the behavior of ameloblastomas,and it is related to many cell mechanisms.BRAF gene mutations have been identified in ameloblastomas,of which the BRAF V600E(valine substituted by glutamic acid at amino acid 600)mutation has been the most common and can be present concomitantly with other mutations that may be involved in its behavior.Targeted therapies have been used as an alternative in the case of resistance or contraindications to conventional treatments.AIM To document the presence of BRAF V600E and additional mutations,their behavior,and targeted therapies in these tumors.METHODS An electronic literature search was conducted according to PRISMA guidelines in PubMed/MEDLINE,Cochrane,EMBASE,and SpringerLink using the terms“ameloblastomas”,“BRAF V600E”,“additional mutations”,and“targeted therapies”.Ameloblastomas were classified according to WHO guidelines.Inclusion criteria were articles in English,published not more than 10 years ago,and studies with laboratory works related to BRAF V600E.Articles were evaluated by two independent reviewers and retrieved for full-text evaluation.The EBLIP Critical Appraisal Checklist was used to evaluate the quality of the eligible studies.Descriptive statistical analysis was performed.RESULTS Two independent reviewers,with a substantial concordance indicated by a kappa coefficient of k=0.76,evaluated a total of 19 articles that were included in this study.The analysis registered 521 conventional ameloblastomas(AM),81 unicystic ameloblastomas(UA),13 ameloblastic carcinomas(AC),three metastatic ameloblastomas(MA),and six peripheral ameloblastomas(PA),of which the histopathological type,anatomic location,laboratory tests,expression of BRAF mutation,and additional mutations were registered.The BRAF V600E mutation was found in 297 AM(57%),63 UA(77.7%),3 AC(23%),1 MA(50%),and 5 PA(83.3%).Follicular type predominated with a total of 116 cases(40%),followed by plexiform type with 63 cases(22.1%).Furthermore,both types presented additional mutations,in which alterations in JAK3 P132T,SMARCB1,PIK3CA,CTNNB1,SMO,and BRAF G606E genes were found.Four case reports were found with targeted therapy to BRAF V600E.CONCLUSION The identification of BRAF V600E and additional mutations as an aid in targeted therapies has been a breakthrough in alternative treatments of ameloblastomas where surgical treatments are contraindicated.

Novel serine/threonine kinase 11 gene mutations in PeutzJeghers syndrome patients and endoscopic management

AIM:To explore mutations in serine/threonine kinase 11(STK11) gene in Peutz-Jeghers syndrome(PJS) with gastrointestinal(GI) hamartomatous polyps.METHODS:Six Japanese PJS patients in 3 families were enrolled in this study.Each of the cases had hamartomatous polyposis in the gastrointestinal tract,including the small intestine,along with mucocutaneous hyperpigmentation.Narrow-band imaging(NBI)-magnification endoscopy was employed to detect microvascular and microsurface irregularities in the GI lesions.NBI magnification findings could be classified into three groups(type A,type B,or type C).Endoscopic polypectomy was performed using double-balloon enteroscopy or colonoscopy.Genomic DNA was extracted from a whole blood sample from each subject.All of the coding exons of STK11 gene,its boundary regions,and the promoter region containing the polymorphic regions were amplified by polymerase chain reaction,and direct sequencing was performed to assess the germline mutations.RESULTS:NBI-magnification endoscopic observation could detect the abnormalities in microvessels and microsurface structures of GI polyps.Overall,we found 5 cases of type A and one case without the examination for the gastric polyps,while there were 4 cases of type B and 2 case of type A for the colorectal polyps.Seventy-nine small-bowel and 115 colorectal polyps over 27 sessions for each were resected endoscopically without significant complications.The only delayed complication included the occurrence of bleeding in a case,and this was successfully managed with hemoclips.Resected polyps contained no malignant components.Based on mutation analysis,all 3 cases in Family I exhibited the +658C>T nonsense mutation in exon 5,which resulted in the production of a truncated protein(Q220X).In Family II,a case had-252C>A and-193C>A in the promoter region.In Family III,a case was found to have the +1062C>G(F342L) mutation in exon 8.CONCLUSION:We found two novel mutations of STK11 in association with PJS.Endoscopic polypectomy of GI polyps in PJS patients appears to be useful to prevent emergency laparotomies and reduce the cancer risk.

Knockdown of Microtubule Associated Serine/threonine Kinase Like Expression Inhibits Gastric Cancer Cell Growth and Induces Apoptosis by Activation of ERK1/2 and Inactivation of NF-κB Signaling

Microtubule-associated serine/threonine kinase(MASTL)functions to regulate chromosome condensation and mitotic progression.Therefore,aberrant MASTL expression is commonly implicated in various human cancers.This study analyzed MASTL expression in gastric cancer vs.adjacent normal tissue for elucidating the association with clinicopathological data from patients.This work was then extended to investigate the effects of MASTL knockdown on tumor cells in vitro.The level of MASTL expression in gastric cancer tissue was assessed from the UALCAN,GEPIA,and Oncomine online databases.Lentivirus carrying MASTL or negative control shRNA was infected into gastric cancer cells.RT-qPCR,Western blotting,cell viability,cell counting,flow cytometric apoptosis and cell cycle,and colony formation assays were performed.MASTL was upregulated in gastric cancer tissue compared to the adjacent normal tissue,and the MASTL expression was associated with advanced tumor stage,Helicobacter pylori infection and histological subtypes.On the other hand,knockdown of MASTL expression significantly reduced tumor cell viability and proliferation,and arrested cell cycle at G2/M stage but promoted tumor cells to undergo apoptosis.At protein level,knockdown of MASTL expression enhanced levels of cleaved PARP1,cleaved caspase-3,Bax and p-ERK1/2 expression,but downregulated expression levels of BCL-2 and p-NF-κB-p65 protein in AGS and MGC-803 cells.MASTL overexpression in gastric cancer tissue may be associated with gastric cancer development and progression,whereas knockdown of MASTL expression reduces tumor cell proliferation and induces apoptosis.Further study will evaluate MASTL as a potential target of gastric cancer therapeutic strategy.

serine/threonine蛋白激酶功能研究进展

蛋白激酶(protein kinase)具有将ATP的γ-磷酸基转移到蛋白质底物特定的氨基酸残基上的潜在催化能力,从而使蛋白质磷酸化。根据底物上氨基酸的特异性,蛋白激酶可以细分为丝/苏氨酸激酶和酪氨酸激酶。在DNA复制和有丝分裂过程中蛋白激酶起调节作用。同时,蛋白激酶在转录过程也起到重要作用,如在转录因子核转位过程的作用、调节转录因子与DNA结合能力、调节转录因子的激活活性。蛋白激酶的磷酸化作用与肿瘤发生关系密切,其可以促使基因表达的改变等一系列细胞的应答发生,最终导致癌症的发生和发展。

Testis Specific Serine/Threonine Protein Kinase 4(TSSK4) Leads to Cell Apoptosis Relying on Its Kinase Activity

Testis specific serine/threonine protein kinase 4（TSSK4） belongs to the TSSK family, and its members play an important role in spermatogenesis and/or spermiogenesis. Mouse TSSK4 has been reported to be expressed exclusively in the testis and can maintain its kinase activity through autophosphorylation at Thr-197. However, its biological function remains poorly understood. Here we found that GFP-TSSK4-overexpressed He La cells showed apoptotic bodies, indicating TSSK4 can lead to apoptosis in vitro. Furthermore, TSSK4 induced apoptosis in different cell lines including He La, Cos-7 and H1299 tested by flow cytometry but not its kinase-dead mutant TSSK4-K54 M. TSSK4 knockout mice showed increased testes weight and decreased apoptotic spermatogonia and spermatocytes at 21 st day after birth tested by TUNEL technology. So TSSK4 was able to induce cell apoptosis in vitro depending on its kinase activity, which leads to abnormal testes weight and apoptosis, shedding light on its function in the process of spermatogenesis and/or spermiogenesis.

A Kelch Motif-Containing Serine/Threonine Protein Phosphatase Determines the Large Grain QTL Trait in Rice

A thorough understanding of the genetic basis of rice grain traits is critical for the improvement of rice （Oryza sativa L.） varieties. In this study, we generated an F2 population by crossing the large-grain japonica cultivar CW23 with Peiai 64 （PA64）, an elite indica small-grain cultivar. Using QTL analysis, 17 QTLs for five grain traits were detected on four different chromosomes. Eight of the QTLs were newly-identified in this study. In particular, qGL3-1, a newly-identified grain length QTL with the highest LOD value and largest phenotypic variation, was fine-mapped to the 17 kb region of chromosome 3. A serine/threonine protein phosphatase gene encoding a repeat domain containing two Kelch motifs was identified as the unique candidate gene corresponding to this QTL. A comparison of PA64 and CW23 sequences revealed a single nucleotide substitution （C→A） at position 1092 in exon 10, resulting in replacement of Asp （D） in PA64 with Glu （E） in CW23 for the 364th amino acid. This variation is located at the D position of the conserved sequence motif AVLDT of the Kelch repeat. Genetic analysis of a near-isogenic line （NIL） for qGL3-1 revealed that the allele qGL3-1 from CW23 has an additive or partly dominant effect, and is suitable for use in molecular marker-assisted selection.

Development of aspartic acid ligation for peptide cyclization derived from serine/threonine ligation

Based on a mechanism analogous to the serine/threonine ligation, the aspartic acid ligation, which is facilitated by the γ-amino alcohol based ligation and oxidation, is developed and applied to the synthesis of cyclic peptides. The γ-hydroxyl group triggers the ring-chain tautomerization via a 6-endo-trig process,while the δ-hydroxyl group facilitates the oxidative cleavage of the vicinal diol to give carboxylic acid.

A defect in the PINOID serine/threonine kinase affects leaf shape in cucumber

Examining the plants in any forest or meadow reveals a remarkable diversity of leaf shape,suggesting the importance of this trait for adaptation to various environmental conditions(reviewed in Nicotra et al.2011).Indeed,leaf shape may be constrained by biomechanical factors and affects thermoregulation,susceptibility to herbivory,the available light for photosynthesis,and water balance.

Tacolimus Postconditioning Alleviates Apoptotic Cell Death in Rats after Spinal Cord Ischemia-reperfusion Injury via Up-regulating Protein-Serine-Threonine Kinases Phosphorylation

The effects of tacrolimus postconditioning on protein-serine-threonine kinases （Akt） phos- phorylation and apoptotic cell death in rats after spinal cord ischemia-reperfusion injury were investi- gated. Ninety male SD rats were randomly divided into sham operation group, ischemia-reperfusion group and tacrolimus postconditioning group. The model of spinal cord ischemia was established by means of catheterization through femoral artery and balloon dilatation. The spinal cord was reperfused 20 min after ischemia via removing saline out of balloon. The corresponding spinal cord segments were excised and determined for Akt activity in spinal cord tissue by using Western blotting at 5, 15, and 60 min after reperfusion respectively. Spinal cord tissue sections were stained immunohistochemically for detection of the phosphorylated Akt expression at 15 min after reperfusion. Flow cytometry was applied to assess apoptosis of neural cells, and dry-wet weights method was employed to measure water content in spinal cord tissue at 24 h after reperfusion. The results showed that the activities of Akt in tarcolimus postconditioning group were significantly higher than those in ischemia-reperfusion group at 5, 15, and 60 min after reperfusion （P〈0.05, P〈0.01）. The Akt activities reached the peak at 15 min after reperfu- sion in ischemia-reperfusion group and tacrolimus postconditioning group. The percentage of apoptotic cells and water content in spinal cord tissue were significantly reduced （P〈0.01） in tacrolimus postcon- ditioning group as compared with those in ischemia-reperfusion group at 24 h after reperfusion. It is concluded that tacrolimus postconditioning can increase Akt activity in spinal cord tissue of rats, inhibit apoptosis of neural cells as well as tissue edema, and thereby alleviate spinal cord ischemia-reperfusion injury.

Serine-threonine protein kinase activation may be an effective target for reducing neuronal apoptosis after spinal cord injury

The signaling mechanisms underlying ischemia-induced nerve cell apoptosis are poorly understood. We investigated the effects of apoptosis-related signal transduction pathways following ischemic spinal cord injury, including extracellular signal-regulated kinase（ERK）, serine-threonine protein kinase（Akt） and c-Jun N-terminal kinase（JNK） signaling pathways. We established a rat model of acute spinal cord injury by inserting a catheter balloon in the left subclavian artery for 25 minutes. Rat models exhibited notable hindlimb dysfunction. Apoptotic cells were abundant in the anterior horn and central canal of the spinal cord. The number of apoptotic neurons was highest 48 hours post injury. The expression of phosphorylated Akt（pAkt） and phosphorylated ERK（p-ERK） increased immediately after reperfusion, peaked at 4 hours（p-Akt） or 2 hours（p-ERK）, decreased at 12 hours, and then increased at 24 hours. Phosphorylated JNK expression reduced after reperfusion, increased at 12 hours to near normal levels, and then showed a downward trend at 24 hours. Pearson linear correlation analysis also demonstrated that the number of apoptotic cells negatively correlated with p-Akt expression. These findings suggest that activation of Akt may be a key contributing factor in the delay of neuronal apoptosis after spinal cord ischemia, particularly at the stage of reperfusion, and thus may be a target for neuronal protection and reduction of neuronal apoptosis after spinal cord injury.

Determination of Carbon and Nitrogen Isotope Fractions in Asparagine, Aspartic Acid, Threonine and Methionine

The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.

Transmembrane serine protease 4 expression in the prognosis of radical resection for biliary tract cancer

BACKGROUND Recent advancements in biliary tract cancer(BTC)treatment have expanded beyond surgery to include adjuvant therapy,yet the prognosis remains poor.Identifying prognostic biomarkers could enhance the assessment of patients who have undergone radical resection for BTC.AIM To determine transmembrane serine protease 4(TMPRSS4)utility as a prognostic biomarker of radical resection for BTC.METHODS Medical records of patients who underwent radical resection for BTC,excluding intrahepatic cholangiocarcinoma,were retrospectively reviewed.The associations between TMPRSS4 expression and clinicopathological factors,overall survival,and recurrence-free survival were analyzed.RESULTS Among the 85 patients undergoing radical resection for BTC,46(54%)were TMPRSS4-positive.The TMPRSS4-positive group exhibited significantly higher preoperative carbohydrate antigen 19-9(CA19-9)values and greater lymphatic invasion than the TMPRSS4-negative group(P=0.019 and 0.039,respectively).Postoperative overall survival and recurrence-free survival were significantly worse in the TMPRSS4-positive group(median survival time:25.3 months vs not reached,P<0.001;median survival time:28.7 months vs not reached,P=0.043,respectively).Multivariate overall survival analysis indicated TMPRSS4 positivity,pT3/T4,and resection status R1 were independently associated with poor prognosis(P=0.032,0.035 and 0.030,respectively).TMPRSS4 positivity correlated with preoperative CA19-9 values≥37 U/mL and pathological tumor size≥30 mm(P=0.016 and 0.038,respectively).CONCLUSION TMPRSS4 is a potential prognostic biomarker of radical resection for BTC.

D-serine合成相关丝氨酸消旋酶在大鼠和癫痫患者海马的分布与细胞定位

目的:观察D-serine合成相关的丝氨酸消旋酶(SR)在大鼠和癫痫病人海马组织的分布与细胞定位特点。方法:成年和幼龄SD大鼠灌流固定、冰冻切片癫痫患者海马硬化石蜡切片,进行SR、SR/NeuN、SR/GFAP免疫荧光染色、激光共聚焦显微镜观察和计数分析。结果:在成年和幼龄大鼠海马的CA1-3和齿状回内均分布有大量SR免疫阳性细胞分布,SR免疫阳性反应主要定位于神经元和星形胶质细胞;与成年相比,幼龄大鼠海马内SR免疫阳性的神经元数量相似,但SR/GFAP阳性星形胶质细胞的数量较多;SR阳性细胞在癫痫患者海马内也有大量分布,其数量明显多于脑出血患者。结论:SR定位于大鼠和癫痫患者海马神经元和星形胶质细胞,其数量分布与发育年龄和癫痫疾病状态呈现一定的相关性,提示D-serine的产生可能参与海马的发育和癫痫疾病过程。

Low-Energy Electron Attachment to Serine Conformers： Shape Resonances and Dissociation Dynamics

Shape resonances of electron-molecule system formed in the low-energy electron attachment to four low-lying conformers of serine （serine 1, serine 2, serine 3, and serine 4） in gas phase are investigated using the quantum scattering method with the non-empirical model potentials in single-center expansion. In the attachment energy range of 0-10 eV, three shape resonances for serine 1, serine 2, and serine 4 and four shape resonances for serine 3 are predicted. The one-dimensional potential energy curves of the temporary negative ions of electron-serine are calculated to explore the correlations between the shape resonance and the bond cleavage. The bond-cleavage selectivity of the different resonant states for a certain conformer is demonstrated, and the recent experimental results about the dissociative electron attachment to serine are interpreted on the basis of present calculations.

Construction of Midgut Tissue-Specific cDNA Library of Bombyx mandarina M. and Isolation and Sequence Analysis of Serine Protease Gene Fragment

[Objective] The aim of the study is to construct cDNA library of midgut tissue of wild silkworm and isolate the serine protease gene. [Method] The midgut tissue-specific cDNA library of wild silkworm was constructed via cDNA Library Construction Kit (TaKaRa), then the serine protease gene was cloned via sequencing of the yielded cDNA library. [Result] The titer of cDNA library reached 6.2×105 pfu/ml, average insert size was about 1.2 kb. The serine protease gene cDNA fragment was obtained from colony sequencing (Accession No: EU672968). The nucleotide sequence of the cloned 854 bp fragment encodes 284 amino acid residues. Homology analyses showed some homology between putative amino acid sequence of the cloned fragment and amino acid sequences of serine proteases from other ten insects. [Conclusion] The results may avail to reveal the resistance of silkworm and wild silkworm to exotic intrusion.

Effects of binuclear copper(Ⅱ)threonine complex on blood glucose, lipids and protection of the hearts and kidneys in diabetic mice

Aim To study the effects of binuclear copper （Ⅱ） threonine complex （Cu2 （Thr）4） as analogue of superoxide dismutase （SOD） on blood glucose, blood lipids and vessels of hearts and kidneys in diabetic mice. Methods Diabetic mouse model was established by intraperitioneal injection of alloxan. Low, middle, and high doses of Cu2（Thr）4 at 0.002%, 0.02% and 0.1% were given respectively to diabetic mice following lavage. The fasting blood glucose was determined after the diabetic mice were given Cu2 （Thr）4 for 0, 30, and 45 d. The diabetic mice were killed on the 45th day. Then glycosylated hemoglobin （HbAlc） and blood lipids were assayed, and pathologic changes in hearts and kidneys stained with HE were observed. Results Compared with the control group in which the diabetic mice were given distilled water, the value of blood glucose reduced significantly in middle dose group （P 〈 0.01 ）, followed by that in low dose group （P 〈 0.05）. TC level reduced markedly and HDL level increased significantly in all three treatment groups （P 〈 0.05）. Especially in middle dose group, cardiac muscle fibers were neatly arranged, nucleus and cytoplasm well distributed, glomeruli showing normal structure, cells well distributed and staining being normal. Conclusion Cu2 （Thr）4 reduces blood glucose, regulates blood lipids, and play protective action on the vessels of hearts and kidneys in diabetic mice. The effects of it in middle dose were better than those of other doses.

Interactions of Anionic and Neutral Serine with Pure and Metal-doped Graphene Studied by Density Functional Theory

We present a theoretical study of interactions of anionic and neutral serine （Ser） on pure or metal-doped graphene surfaces using density functional theory calculations. Interactions of both types of Ser with the pure graphene surface show weak non-covalent interactions due to the formation of-COOH…π, -COO^-…π, and -OH…π interactions. On metal- doped graphene, covalent interactions to the surface dominate, due to the formation of strong metal-O and O-metal-O interactions. Furthermore, the doped Fe, Cr, Mn, A1, or Ti enhances the ability of graphene to attract both types of Ser by a combination of the adsorption energy, the density of states, the Mulliken atomic charges, and differences of electron density. At the same time, the interaction strengths of anionic Ser on various graphene surfaces are stronger than those of neutral Ser. These results provide useful insights for the rational design and development of graphene-based sensors for the two forms of Ser by introducing appropriate doped atoms. Ti and Fe are suggested to be the best choices among all doped atoms for the anionic Ser and neutral Ser, respectively.

Evaluation of cytotoxic and anti-tumor activity of partially purified serine protease isolate from the Indian earthworm Pheretima posthuma

Objective:To isolate,partially purify and evaluate the cytotoxic and antitumor activity of a serine protease from the chosen Indian earthworm Pheretima posthuma.Methods:Whole animal extract was prepared and purified its protein constituents by size and charge based chromatographic separation techniques using Sephadex G-50 and DEAE-Cellulose resin respectively.Average molecular weight of the protein isolate was determined and analyzed for its cytotoxic property against Vero cells in different dilutions(1:20 and 1:40)and anti-tumor activity by MTT assay(a colorimetric assay)using breast cancer cell line MCF-7,with tamoxifen as standard.Results:One of the protein constituents after purification was characterized as serine protease by Caseinolytic plate diffusion assay.Average molecular weight of this purified isolate was determined,by SDS-PAGE analysis with standard protein ladder,as of 15 kDa.The performed tests suggested that the 15kDa fraction has potent cytotoxic activity and satisfactory antitumor activity as well in vitro.Conclusions:Exact molecular mechanism of the cytotoxic and antitumor activities is yet to be explored and currently we are working on ultra-purification and biophysical characterization of this fraction.Further investigation into the mechanism(s)of cytotoxic and antitumor activities at molecular level would be useful in treatment of various classes of cancer and viral infections in future.

Growth,digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp Ctenopharyngodonidella fed graded levels of dietary threonine

Background： This study was carried out to investigate effects of threonine levels on growth, digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp （ Ctenopharyngodonidella）. Results： Weight gain, specific growth rate, feed intake and feed efficiency were significantly improved by dietary threonine （P 〈 0.05）. Intestinal activities of trypsin, chymotrypsin, alpha-amylase, lipase, alkaline phosphatase, y-glutamyl transpeptidase and creatine kinase took the similar trends. Contents of malondialdehyde and protein carbonyl in intestine and hepatopancreas were significantly decreased by dietary optimal threonine supplementation （P 〈 0.05）. Anti-superoxide anion capacity, anti-hydroxyl radical capacity, glutathione content and activities of superoxide dismutase, catalase and glutathione-S-transferase in intestine and hepatopancreas were enhanced by dietary threonine （P 〈 0.05）. Conclusions： Dietary threonine could improve growth, enhance digestive and absorptive capacity and antioxidant status in intestine and hepatopancreas of sub-adult grass carp. The dietary threonine requirement of sub-adult grass carp （441.9-1,013.4 g） based on weight gain was 11.6 g/kg diet or 41.5 g/kg of dietary protein by quadratic regression analysis.

Simulation of water potential for the electronic structure of serine

First-principles, all-electron, ab initio calculations have been performed to construct an equivalent water potential for the electronic structure of serine （Ser） in solution. The calculation is composed of three steps. The first step is to search for the configuration of the Ser _ nH2O system with a minimum energy. The second step is to calculate the electronic structure of Ser with the water molecule potential via the self-consistent cluster-embedding method （SCCE）, based on the result obtained in the first step. The last step is to calculate the electronic structure of Set with the dipole potential after replacing the water molecules with dipoles. The results show that the occupied states of Ser are raised by about 0.017 Ry on average due to the effect of water. The water effect can be successfully simulated by using the dipole potential. The obtained equivalent potential can be applied directly to the electronic structure calculation of protein in solution by using the SCCE method.