• 한국미생물·생명공학회지
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• 제49권1호
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• pp.65-74
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• 2021

Serine proteases are the most versatile proteolytic enzymes with tremendous applications in various industrial processes. This study was designed to investigate the biochemical properties, critical residues, and the catalytic potential of alkaline serine protease using in-silico approaches. The primary sequence was analyzed using ProtParam, SignalP, and Phyre2 tools to investigate biochemical properties, signal peptide, and secondary structure, respectively. The three-dimensional structure of the enzyme was modeled using the MODELLER program present in Discovery Studio followed by Molecular Dynamics simulation using GROMACS 5.0.7 package with CHARMM36m force field. The proteolytic potential was measured by performing docking with casein- and keratin-enriched residues, while the effect of the inhibitor was studied using phenylmethylsulfonyl fluoride, (PMSF) applying GOLDv5.2.2. Molecular weight, instability index, aliphatic index, and isoelectric point for serine protease were 39.53 kDa, 27.79, 82.20 and 8.91, respectively. The best model was selected based on the lowest MOLPDF score (1382.82) and DOPE score (-29984.07). The analysis using ProSA-web revealed a Z-score of -9.7, whereas 88.86% of the residues occupied the most favored region in the Ramachandran plot. Ser327, Asp138, Asn261, and Thr326 were found as critical residues involved in ligand binding and execution of biocatalysis. Our findings suggest that bioengineering of these critical residues may enhance the catalytic potential of this enzyme.

• BMB Reports
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• 제41권2호
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• pp.102-107
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• 2008

Extracellular proteases play an important role in a wide range of host physiological events, such as food digestion, extracellular matrix degradation, coagulation and immunity. Among the large extracellular protease family, serine proteases that contain a "paper clip"-like domain and are therefore referred to as CLIP-domain serine protease (clip-SP), have been found to be involved in unique biological processes, such as immunity and development. Despite the increasing amount of biochemical information available regarding the structure and function of clip-SPs, their in vivo physiological significance is not well known due to a lack of genetic studies. Recently, Drosophila has been shown to be a powerful genetic model system for the dissection of biological functions of the clip-SPs at the organism level. Here, the current knowledge regarding Drosophila clip-SPs has been summarized and future research directions to evaluate the role that clip-SPs play in Drosophila immunity are discussed.

• 한국수산과학회지
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• 제48권2호
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• pp.178-186
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• 2015

Protease inhibitors (PI) of trypsin and papain as target proteases from the roe of bastard halibut Paralichthys olivaceus were fractionated out using ammonium sulfate precipitation (A), DEAE 650M anion exchange chromatography (D), and Sephacryl S-300 gel filtration (S). The recovery percentages of the fractions with the strongest inhibitory activity for each fractionation method were 13% for the A4 fraction, 21.2% for the D3 fraction, and 21.3% for the S2 fraction, with specific inhibitory activities of the fractions toward trypsin and casein of 168, 139, and 218 U/mg, respectively, while no inhibition of papain was observed. The $IC_{50}$ for the trypsin-specific substrate $N{\alpha}$-benzoyl-$\small{L}$-arginine-p-nitroanilide (BAPNA) was 0.65, 1.55, 2.26, and 2.85 mg/mL for the A4, S2, A3, and D3 fractions, respectively. These results suggest that chromatographic fractionation methods (D and S) based on the molecular mass and charge of the protein were more effective at fractionating PI than was ammonium sulfate precipitation based on protein solubility, and that the bastard halibut roe extract acts as a serine protease inhibitor. Therefore, the PI fraction from fish roe might be useful for inhibiting proteases in foodstuffs, and could constitute an alternative food-grade inhibitor for the surimi industry.

• Journal of Microbiology and Biotechnology
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• 제21권2호
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• pp.129-135
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• 2011

Cloning and characterization of the gene encoding a solvent-tolerant protease from the haloalkaliphilic bacterium Geomicrobium sp. EMB2 are described. Primers designed based on the N-terminal amino acid sequence of the purified EMB2 protease helped in the amplification of a 1,505-bp open reading frame that had a coding potential of a 42.7-kDa polypeptide. The deduced EMB2 protein contained a 35.4-kDa mature protein of 311 residues, with a high proportion of acidic amino acid residues. Phylogenetic analysis placed the EMB2 gene close to a known serine protease from Bacillus clausii KSM-K16. Primary sequence analysis indicated a hydrophobic inclination of the protein; and the 3D structure modeling elucidated a relatively higher percentage of small (glycine, alanine, and valine) and borderline (serine and threonine) hydrophobic residues on its surface. The structure analysis also highlighted enrichment of acidic residues at the cost of basic residues. The study indicated that solvent and salt stabilities in Geomicrobium sp. protease may be accorded to different structural features; that is, the presence of a number of small hydrophobic amino acid residues on the surface and a higher content of acidic amino acid residues, respectively.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2004년도 춘계학술대회
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• pp.129-129
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• 2004

• Biomolecules & Therapeutics
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• 제3권2호
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• pp.165-170
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• 1995

The biochemical properties of the fibrinolytic protease of 50,800 Da isolated from the venom of Kgdistrodon blomhoffi brevicaudus were characterized. The enzyme hydrolyzed the carboxyl side of arginine in the synthetic chromogenic peptides, N-Benzoyl-Phe-Val-Arg-pNA and N-p-Tosyl-Gly-Pro-Arg-pNA, and the enzyme activity was inhibited by phenylmethylsulfonylfluoride indicating that the enzyme belongs to the serine protease family. The pretense showed maximum activity at pH 7.5 and inhibited by ZnCl$_2$, CuSO$_4$, but not by soybean trypsin inhibitor, pepstatin A, 2-mercaptoethanol and EDTA. The fm value determined with N-p-Tosyl-Gly-Pro-Arg-pNA was 0.2 mM. The thrombolytic activity of the purified enzyme was evaluated by platelet aggregation test in rabbits. While the platelet count ratio in blood of the rabbits injected with thrombin alone declined from 1.0 to 0.6 within 7 min and maintained around 0.6 for 24 hours thereafter, the ratio rapidly recovered from around 0.6 to 0.8 in 1 hr, to 1.0 in 24 hrs when the rabbits were sequentially treated with thrombin and the purified enzyme. The result showed that the serine protease from A. blomhoffi brevicoudus of 50,800 Da had a thrombolytic activity in vivo and the enzyme might be developed as a therapuetic agent for the treatment of thrombic disease.

• BMB Reports
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• 제44권6호
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• pp.387-392
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• 2011

To investigate the molecular scavenging capabilities of the larvae of Hermetia illucens, two serine proteases (SPs) were cloned and characterized. Multiple sequence alignments and phylogenetic tree analysis of the deduced amino acid sequences of Hi-SP1 and Hi-SP2 were suggested that Hi-SP1 may be a chymotrypsin- and Hi-SP2 may be a trypsin-like protease. Hi-SP1 and Hi-SP2 3-D homology models revealed that a catalytic triad, three disulfide bonds, and a substrate-binding pocket were highly conserved, as would be expected of a SP. E. coli expressed Hi-SP1 and Hi-SP2 showed chymotrypsin or trypsin activities, respectively. Hi-SP2 mRNAs were consistently expressed during larval development. In contrast, the expression of Hi-SP1 mRNA fluctuated between feeding and molting stages and disappeared at the pupal stages. These expression pattern differences suggest that Hi-SP1 may be a larval specific chymotrypsin-like protease involved with food digestion, while Hi-SP2 may be a trypsin-like protease with diverse functions at different stages.

• Journal of Microbiology and Biotechnology
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• 제25권9호
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• pp.1449-1459
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• 2015

A novel proteolytic enzyme with fibrinolytic activity, FSP3, was purified from the recently isolated Streptomyces sp. P3, which is a novel bacterial strain isolated from soil. FSP3 was purified to electrophoretic homogeneity by ammonium sulfate precipitation, anion exchange, and gel filtration. FSP3 is considered to be a single peptide chain with a molecular mass of 44 kDa. The maximum activity of the enzyme was observed at 50℃ and pH 6.5, and the enzyme was stable between pH 6 and 8 and below 40℃. In a fibrin plate assay, FSP3 showed more potent fibrinolytic activity than urokinase, which is a clinical thrombolytic agent acting as a plasminogen activitor. The activity was strongly inhibited by the serine protease inhibitor PMSF, indicating that it is a serine protease. Additionally, metal ions showed different effects on the activity. It was significantly suppressed by Mg²⁺ and Ca²⁺ and completely inhibited by Cu²⁺, but slightly enhanced by Fe²⁺. According to LC-MS/MS results, its partial amino acid sequences are significantly dissimilar from those of previously reported fibrinolytic enzymes. The sequence of a DNA fragment encoding FSP3 contained an open reading frame of 1287 base pairs encoding 428 amino acids. FSP3 is a bifunctional enzyme in nature. It hydrolyzes the fibrin directly and activates plasminogen, which may reduce the occurrence of side effects. These results suggest that FSP3 is a novel serine protease with potential applications in thrombolytic therapy.

• 수산해양교육연구
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• 제26권4호
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• pp.808-822
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• 2014

넙치 (Paralichthys olivaceus)로부터 elastase-like serine protease (PoElSp)를 암호화하는 cDNA를 클로닝하여 그 서열을 분석한 결과, PoElSp 유전자는 269 아미노산을 암호화하는 978염기쌍으로 구성되었다. PoElSp 유전자의 조직 특이적 발현 양상을 RT-PCR법으로 조사한 결과, 간, 비장 및 소장에서 그 발현이 크게 나타났다. lipopolysaccharide (LPS)로 인위적 세균감염을 유도한 후, 1시간째에 콩팥에서, 3시간째에는 근육에서, PoElSp 유전자의 발현이 크게 증가하였다. 또한, 이 유전자의 발현은 비장에서 LPS 주입 후 1-24시간동안 점차로 증가하였다. pro-mature PoElSp (proPoElSp)에 해당하는 cDNA를 pET32a 벡터 시스템을 이용하여 대장균에서 발현시켰다. 이 재조합 proPoElSp 단백질의 활성은 gelatin zymography 방법과 합성형광 Z-Phe-Arg-AMC의 분해법을 이용하여 측정하였다. 단백질 분해효소 활성을 위한 최적 pH는 7.5였다. 실험결과들을 종합하면, PoElSp 단백질은 면역 반응에서 중추적 역할을 하리라 판단된다.

• 농업생명과학연구
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• 제45권6호
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• pp.201-212
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• 2011

인천 연안의 심하게 오염된 갯벌로부터 강력한 세포외 알카리성 단백질 분해효소를 생산하는 호알카리성 Bacillus clausii I-52를 분리하였으며, 이 균주로부터 알카리성 단백질 분해효소의 유전자를 cloning하여 서열 분석을 하였다. Chromosome 서열이 완전히 밝혀진 Bacillus subtilis의 서열을 기초로 하여 알카리성 단백질 분해효소 및 promoter를 포함하도록 primer를 고안하여 PCR을 수행하여 2,277 bp의 DNA 단편을 얻었으며 BLAST 분석 결과 29 개의 아미노산으로 이루어진 signal peptide, 77 개의 아미노산으로 이루어진 propeptide 및 275 개의 아미노산을 갖는 활성형의 BCAP으로 구성된 총 381 개의 아미노산을 코딩하는 1,143 bp의 open reading frame을 확인하였다. 활성형 BCAP의 N-말단 아미노산은 Ala이며, 분자량 및 pI 값은 각각 27698.7 Da과 6.30으로 계산되었다. 아미노산 상동성을 분석한 결과, B. subtilis 유래의 nattokinase precursor 및 B. subtilis BSn5 유래의 subtilisin E precursor와 99%의 서열 상동성을 나타내어 B. clausii I-52 유래의 BCAP은 subtilisin 계열의 단백질 분해효소임을 확인하였다. E. coli BL21(DE3)에서 발현한 재조합 BCAP는 N-Suc-Ala-Ala-Pro-Phe-pNA 를 효율적으로 분해하였다. Refolding한 재조합 BCAP은 전형적인 serine protease inhibitor인 PMSF에 의하여 강하게 효소 활성이 억제됨으로써 serine protease 계열의 단백질 분해효소임을 알 수 있었다.