Gene Cloning and Enzymatic Properties of an Intracellular Maltogenic Amylase from Bacillus sp. B110
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摘要: 目的:对菌株Bacillus sp. B110的胞内麦芽糖淀粉酶BMAL进行基因克隆、异源表达、纯化及酶学性质研究,为后期开发新的淀粉加工用酶打下基础。方法:使用PCR技术对Bacillus sp. B110的胞内麦芽糖淀粉酶bmal基因序列进行全长克隆,异源表达,使用Ni2+-NTA进行纯化,再对其酶学特性进行测定,使用序列分析工具BioEdit、MEGA等对其氨基酸序列进行分析,使用AlphaFold2对其三级结构进行预测分析。结果:BMAL基因全长1770 bp,编码一个589氨基酸残基的蛋白。重组酶rBMAL经Ni2+-NTA亲和层析纯化后,SDS-PAGE电泳结果显示其分子量大小为63 kDa。氨基酸序列分析和三维建模表明BMAL与来源于B.subtilis 168和B.subtilis SUH4-2的麦芽糖淀粉酶有较高的一致性,且BMAL具有一个麦芽糖淀粉酶所独有的N端结构域以及由Asp328-Glu357-Asp424三个氨基酸残基所构成的催化中心。重组酶rBMAL最适反应温度为45 ℃,最适反应pH为6.0。重组酶rBMAL在30 ℃条件下保藏7 h残留酶活为60%,但在60 ℃条件下保藏2 h残留酶活力下降98%,说明BMAL对热敏感。重组酶rBMAL在4 ℃,pH7.0~9.5保藏12 h活性稳定。当存在1 mmol/L的金属离子Mg2+时,重组酶rBMAL活力提高36%,而Ni2+、Fe3+、Co2+、Cu2+、Zn2+、Al3+、Ca2+对重组酶rBMAL有抑制作用,酶活力减少85%~48%。有机溶剂和化学试剂甲醇、乙醇、丙酮、异腈、EDTA和SDS对重组酶rBMAL有较强的抑制作用,酶活力减少至32.3%~64.8%。底物特异性实验结果证实BMAL最适底物为环精糊。结论:Bacillus sp. B110的胞内麦芽糖淀粉酶BMAL具有良好的催化特性和pH稳定性,在面包烘焙工业上具有潜在的应用价值。
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关键词:
- Bacillus sp. B110 /
- BMAL /
- 麦芽糖淀粉酶 /
- 基因克隆 /
- 酶学特性
Abstract: Objective: To study enzymatic properties of intracellular maltogenic amylase (BMAL) in Bacillus sp. B110, purification, gene cloning, heterologous expression and purification were performed. It laid a foundation for later research on the development of new starch processing enzymes. Method: The full-length of BMAL gene was amplified by PCR and over-expressed and heterologous expressed in Escherichia coli. The recombinant enzyme was purified with nickel affinity chromatography (Ni2+-NTA), and its enzymatic characteristic were determined. The amino acid sequence of BMAL was analyzed by sequence analysis tools BioEdit and MEGA tools, and the three-dimensional model was predicted by alpha fold2. Results: The nucleotide sequence analysis revealed an open reading frame (ORF) of 1770 bp encoded a putative protein of 589 aa residues. The recombinant enzyme was purified with nickel affinity chromatography (Ni2+-NTA). SDS-PAGE analysis of the purified enzyme revealed that the molecular mass of BMAL was 63 kDa. The primary structure of BMAL was similar to those of MAases from B. subtilis 168 and B. subtilis SUH4-2, such as possession of an extra domain at its N-terminal and had a catalytic triad Asp328-Glu357-Asp424. The purified recombinant enzyme rBMAL had an optimum temperature of 45 ℃ and an optimum pH around 6.0. The rBMAL retained about 60% activity after 7 h of incubation at below 30 ℃, but it lost 98% of the original activity after 2 h of incubation at 60 ℃. These results revealed that the rBMAL was inthermostability. The activity of rBMAL was stable in pH7.0~9.5 at 4 ℃ for 12 h. In the presence of 1 mmol/L metal ion Mg2+, the activity of rBMAL increased by 36%, while 1 mmol/L Ni2+, Fe3+, Co2+, Cu2+, Zn2+, Al3+, Ca2+ inhibited the activity of rBMAL, which decreased by 85%~48%. The recombinant enzyme activity was inhibited by methanol, acetone, ethanol, acetonitrile, EDTA and SDS, and the enzyme activity was decreased to 32.3%~64.8%. Conclusion: The intracellular maltose amylase BMAL from Bacillus sp. B110 had high catalytic capacity and pH stability, which had potential application in bread baking industry.-
Key words:
- Bacillus sp. B110 /
- BMAL /
- maltogenic amylase /
- gene cloning /
- enzymatic properties
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表 1 金属离子和化学试剂对重组酶rBMAL酶活力的影响
Table 1. Effect of metal ions and chemical reagents on the activity of rBMAL
金属离子(1 mmol/L) 相对酶活(%) 化学试剂 相对酶活(%) CK 100±1.22b CK 100.00±6.94a Al3+ 34.04±0.32de Methanol 32.33±3.75f Fe3+ 23.29±3.10f Ethanol 55.43±4.67e Zn2+ 36.80±1.82d Acetone 58.96±4.45de Co2+ 15.00±3.01g Isopropanol 54.22±0.82e Cu2+ 26.15±3.35f Acetonitrile 67.00±3.21c Ni2+ 31.14±4.60e SDS 80.80±2.43b K+ 56.10±1.81c Tween 80 98.53±3.64a Mn2+ 98.91±1.08b TritonX-100 97.94±4.56a Mg2+ 136.77±0.41a EDTA 63.82±3.37cd Ca2+ 52.23±1.82c 注:采用邓肯氏新复极差法检验进行统计分析,不同小写字母表示差异显著,P<0.05。 表 2 重组酶rBMAL的动学常数
Table 2. Apparent kinetic constants of rBMAL
底物 单位酶活
(U·mg−1)Km
(mg·mL−1)kcat
(s−1)kcat/Km
(mL·mg−1·s−1)可溶性淀粉 32.5 20.2 143.33 7.10 直链淀粉 24 15.89 119.07 7.49 普鲁兰糖 68.2 3.35 302.09 90.18 β-环糊精 85 2.85 374.85 131.53 -
[1] MABROUK S B, MESSAOND E B, AYADI D, et al. Cloning and sequencing of an original gene encoding a maltogenic amylase from Bacillus sp. US149 strain and characterization of the recombinant activity[J]. Mol Biotechnol,2008,38(3):211−219. doi: 10.1007/s12033-007-9017-4 [2] HWA P K, JIP K T, KYOU C T, et al. Structure, specificity and function of cyclomaltodextrinase, a multispecific enzyme of the alpha-amylase family[J]. Biochimica Et Biophysica Acta,2000,1478(2):165−185. doi: 10.1016/S0167-4838(00)00041-8 [3] LI D, PARK S H, SHIM J H, et al. In vitro enzymatic modification of puerarin to puerarin glycosides by maltogenic amylase[J]. Carbohydrate Research,2004,339(17):2789−2797. doi: 10.1016/j.carres.2004.09.017 [4] KOLCUOGLU Y, COLAK A, FAIZ O, et al. Cloning, expression and characterization of highly thermo- and pH-stable maltogenic amylase from a thermophilic bacterium Geobacillus caldoxylosilyticus TK4[J]. Process Biochemistry,2010,45(6):821−828. doi: 10.1016/j.procbio.2010.02.001 [5] CHEN X, ZHANG L, LI X, et al. Impact of maltogenic α-amylase on the structure of potato starch and its retrogradation properties[J]. Int J Biol Macromol,2020,145:325−331. doi: 10.1016/j.ijbiomac.2019.12.098 [6] RUAN Y, XU Y, ZHANG W, et al. A new maltogenic amylase from Bacillus licheniformis R-53 significantly improves bread quality and extends shelf life[J]. Food Chemistry,2020,344(15):128599. [7] HAGHIGHAT K S, KASAAI M R, MILANI J M, et al. Optimization of encapsulation of maltogenic amylase into a mixture of maltodextrin and beeswax and its application in gluten-free bread[J]. Journal of Texture Studies,2020,51(4):631−641. doi: 10.1111/jtxs.12516 [8] CHA H J, YOON H G, KIM Y W, et al. Molecular and enzymatic characterization of a maltogenic amylase that hydrolyzes and transglycosylates acarbose[J]. European Journal of Biochemistry,1998,253(1):251−262. doi: 10.1046/j.1432-1327.1998.2530251.x [9] LEE H S, KIM M S, CHO H S, et al. Cyclomaltodextrinase, neopullulanase, and maltogenic amylase are nearly indistinguishable from each other[J]. Journal of Biological Chemistry,2002,277(24):21891−21897. doi: 10.1074/jbc.M201623200 [10] CHO H Y, KIM Y W, KIM T J, et al. Molecular characterization of a dimeric intracellular maltogenic amylase of Bacillus subtilis SUH4-2[J]. Biochimica et Biophysica Acta,2000,1478(2):333−340. doi: 10.1016/S0167-4838(00)00037-6 [11] WANG Y C, HU H F, MA J W, et al. A novel high maltose-forming α-amylase from Rhizomucor miehei and its application in the food industry[J]. Food Chem,2020,305:125447. doi: 10.1016/j.foodchem.2019.125447 [12] FINCAN S A, ÖZDEMIR S, KARAKAYA A, et al. Purification and characterization of thermostable α-amylase produced from Bacillus licheniformis So-B3 and its potential in hydrolyzing raw starch[J]. Life Sci,2021,264:118639. doi: 10.1016/j.lfs.2020.118639 [13] JIN S B, MYO J K, HYUNJU C, et al. Enhanced transglycosylation activity of thermus maltogenic amylase in acetone solution[J]. Food Science & Biotechnology,2003,12(6):639−643. [14] KWON K S, AUH J H, CHOI S K, et al. Characterization of branched oligosaccharides produced by Bacillus licheniformis maltogenic amylase[J]. Journal of Food Science,1999,64(2):258−261. doi: 10.1111/j.1365-2621.1999.tb15878.x [15] JUNG W K, YUNG H K, HEE S L, et al. Molecular cloning and biochemical characterization of the first archaeal maltogenic amylase from the hyperthermophilic archaeon Thermoplasma volcanium GSS1[J]. Biochimica et Biophysica Acta,2007,1774(5):661−669. doi: 10.1016/j.bbapap.2007.03.010 [16] OH K W, KIM M J, KIM H Y, et al. Enzymatic characterization of a maltogenic amylase from Lactobacillus gasseri ATCC 33323 expressed in Escherichia coli[J]. FEMS Microbiology Letters,2005,252(1):175−181. doi: 10.1016/j.femsle.2005.08.050 [17] JI H, LI X, JIANG T, et al. A novel amylolytic enzyme from Palaeococcus ferrophilus with malto-oligosaccharide forming ability belonging to subfamily GH13_20[J]. Food Bioscience,2022,45:101498. doi: 10.1016/j.fbio.2021.101498 [18] ZHOU J, LI Z, ZHANG H, et al. Novel maltogenic amylase CoMA from Corallococcus sp. strain EGB catalyzes the conversion of maltooligosaccharides and soluble starch to maltose[J]. Appl Environ Microbiol,2018,84(14):e00152−18. [19] HUANG Z, NI G, WANG F, et al. Characterization of a thermostable lichenase from Bacillus subtilis B110 and its effects on β-glucan hydrolysis[J]. Journal of Microbiology and Biotechnology,2022,32(4):484−492. doi: 10.4014/jmb.2111.11017 [20] 陈允妲, 李雪亮, 赵晓艳, 等. Streptomyces lavendulae X33海藻糖合酶基因克隆及酶学特性[J]. 江西农业大学学报,2021,43(4):901−909. [CHEN Y D, LI X L, ZHAO X Y, et al. Cloning and characterization of trehalose synthase gene of Streptomyces lavendulae X33[J]. Journal of Jiangxi Agricultural University,2021,43(4):901−909. [21] BOULANGER P. Purification of bacteriophages and SDS-PAGE analysis of phage structural proteins from ghost particles[J]. Methods in Molecular Biology,2009,502:227−238. [22] M M BRADFORD. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding[J]. Analytical Biochemistry,1976,72(1−2):248−254. doi: 10.1016/0003-2697(76)90527-3 [23] MILLER G L. Use of dinitrosalicylic acid reagent for determination of reducing sugar[J]. Analytical Biochemistry,1959,31(3):426−428. [24] 李钰娜, 宋英达, 任晨霞. Bacillus sp. L1胞外蛋白酶EL1基因克隆及酶学性质分析[J]. 食品工业科技,2020,41(5):119−123. [[LI Y N, SONG Y D, REN C X. Cloning and characterization of extracellular protease EL1 gene of Bacillus sp. L1[J]. Science and Technology of Food Industry,2020,41(5):119−123. [25] KUNST F, OGASAWARA N, MOSZER I, et al. The complete genome sequence of the Gram-positive bacterium Bacillus subtilis[J]. Nature,1997,390(6657):249−256. doi: 10.1038/36786 [26] JUNG T Y, LI D, PARK J T, et al. Association of novel domain in active site of archaic hyperthermophilic maltogenic amylase from Staphylothermus marinus[J]. Journal of Biological Chemistry,2012,287(11):7979−7989. doi: 10.1074/jbc.M111.304774 [27] KIM I C, CHA J H, KIM J R, et al. Catalytic properties of the cloned amylase from Bacillus licheniformis[J]. Journal of Biological Chemistry,1992,267(31):22108−22114. doi: 10.1016/S0021-9258(18)41642-0 [28] OHDAN K, KURIKI T, TAKATA H, et al. Cloning of the cyclodextrin glucanotransferase gene from alkalophilic Bacillus sp. A2-5a and analysis of the raw starch-binding domain[J]. Applied Microbiology Biotechnology,2000,53(4):430−434. doi: 10.1007/s002530051637 [29] HONDOH H, KURIKI T, MATSUURA Y. Three-dimensional structure and substrate binding of Bacillus stearothermophilus neopullulanase[J]. Journal of Molecular Biology,2003,326(1):177−188. doi: 10.1016/S0022-2836(02)01402-X [30] KIM J S, CHA S S, KIM H J, et al. Crystal structure of a maltogenic amylase provides insights into a catalytic versatility[J]. Journal of Biological Chemistry,1999,274(37):26279−26286. doi: 10.1074/jbc.274.37.26279 [31] AROOB I, AHMAD N, ASLAM M, et al. A highly active α-cyclodextrin preferring cyclomaltodextrinase from Geobacillus thermopakistaniensis[J]. Carbohydrate Research,2019:4811−4818. [32] RUAN Y, ZHANG R, XU Y. Directed evolution of maltogenic amylase from Bacillus licheniformis R-53: Enhancing activity and thermostability improves bread quality and extends shelf life[J]. Food Chem,2022,381:132222. doi: 10.1016/j.foodchem.2022.132222