想要獲得高質(zhì)量蛋白晶體一般需要克服3個難題：1、獲得純度高的，均一的蛋白樣品；2，篩選可結(jié)晶的條件；3，優(yōu)化結(jié)晶條件，最后獲得高質(zhì)量的單晶；其中，篩選可結(jié)晶的條件是獲得蛋白質(zhì)晶體的主要瓶頸之一；

    Jena Biosource品牌中有一系列蛋白結(jié)晶研究所要用的試劑和耗材，以下給大家介紹一下Jena里面暢銷的蛋白結(jié)晶條件篩選試劑盒。

1、JBScreen Basic

JBScreen Basic是基于稀疏矩陣法的蛋白結(jié)晶試劑盒，包含了96種篩選條件，整套試劑盒分為4個小規(guī)格，每個小規(guī)格包含24種條件，24個條件分別密封在螺旋蓋試管中，每管10ml,可以隨時使用。Jena里面的蛋白結(jié)晶篩選試劑盒不包含二甲砷酸鹽，用MES進行替代。

二甲砷酸鹽，含砷，是有毒物質(zhì)

1、      致癌物質(zhì)；

2、      吸入后對人體有害，刺激眼睛和皮膚，長時間接觸，可導致腎臟和肝臟受損；

3、      能與自由巰基反應(yīng)，可以與半胱氨酸硫共價結(jié)合，所以存在蛋白構(gòu)象受到嚴重影響的風險；

2、 JBScreen Classic

      這個系列是Jena品牌中最初推出的經(jīng)典的結(jié)晶條件試劑盒，在文獻中的應(yīng)用以每年30%的速度增長；這個試劑盒包含了240個篩選條件，涵蓋了各種有效沉淀劑和Buffer。整套試劑盒分成了10小規(guī)格，每個規(guī)格包含了24個條件，如果只想要其中某些條件，是可以單獨購買小規(guī)格試劑盒的；

         3、JBScreen pentaerythritol

      基于兩種新奇的沉淀劑，季戊四醇丙氧基化物和季戊四醇乙基化物，用于生物大分子最初結(jié)晶條件的篩選。兩者都包含一個季戊四醇的支鏈型高分子。因此他們不同于傳統(tǒng)的沉淀劑（如MPD和PEG）。另外，季戊四醇聚合物具有冷凍保護劑的功能，蛋白晶體在這些高濃度的沉淀劑中生長，并能夠由晶滴直接冷凍；

     參考文獻：

• Sheu-Gruttadauria et al. (2019) Beyond the seed: structural basis for supplementary microRNA targeting by human Argonaute2. The EMBO Journal e101153.
• Pozzi et al. (2019) Evidence of Destabilization of the Human Thymidylate Synthase (hTS) Dimeric Structure Induced by the Interface Mutation Q62R. Biomolecules DOI:10.3390/biom9040134.
• Deka et al. (2018) Structural and biochemical studies on the role of active site Thr166 and Asp236 in the catalytic function of D-Serine deaminase from Salmonella typhimurium. Biochem. Biophys. Res. Commun. 504:40.
• Dall et al. (2018) Structural and functional analysis of cystatin E reveals enzymologically relevant dimer and amyloid fibril states. J. Biol. Chem. 293:13151.
• Rinaldi et al. (2018) Crystallization and initial X-ray diffraction analysis of the multi-domain Brucella blue light-activated histidine kinase LOV-HK in its illuminated state. Biochem. Biophys. Rep. 16:39.
• Flores-Ibarra et al. (2018) Crystallization of a human galectin-3 variant with two ordered segments in the shortened N-terminal tail. Sci. Rep. 8:9835.
• Bernedo-Navarro et al. (2018) Structural Basis for the Specific Neutralization of Stx2a with a Camelid Single Domain Antibody Fragment. Toxins 10:108.
• Zeng et al. (2017) Structural basis of host recognition and biofilm formation by Salmonella Saf pili. eLife DOI:10.7554/eLife.28619.
• Oiki et al. (2017) Alternative substrate-bound conformation of bacterial solute-binding protein involved in the import of mammalian host glycosaminoglycans. Sci. Rep. 7:17005.
• Jansson et al. (2017) The interleukin-like epithelial-mesenchymal transition inducer ILEI exhibits a non-interleukin-like fold and is active as a domain-swapped dimer. J. Biol. Chem. 292:15501.
• McPhail et al. (2017) The Molecular Basis of Aichi Virus 3A Protein Activation of Phosphatidylinositol 4 Kinase IIIβ, PI4KB, through ACBD3. Structure 25:121.
• Songsiriritthigul et al. (2017) Crystal structure of the N-terminal anticodon-binding domain of the nondiscriminating aspartyl-tRNA synthetase from Helicobacter pylori. Acta Cryst F 73:62.
• Yokoyama et al. (2017) Large-scale crystallization and neutron crystallographic analysis of HSP70 in complex with ADP. Acta Cryst F 73:555.

• Corvaglia et al. (2019) Carboxylate-functionalized foldamer inhibitors of HIV-1 integrase and Topoisomerase 1: artificialanalogues of DNA mimic proteins. Nucleic Acids Research DOI:10.1093/nar/gkz352.
• Deka et al. (2017) Comparative structural and enzymatic studies on Salmonella typhimurium diaminopropionate ammonia lyase reveal its unique features. J. Struct. Biol. DOI:10.1016/j.jsb.2017.12.012.
• Moonens et al. (2015) Structural insight in the inhibition of adherence of F4 fimbriae producing enterotoxigenic Escherichia coli by llama single domain antibodies. Veterinary Research 46:14.
• Zano et al. (2014) Structure of an unusual S-adenosylmethionine synthetase from Campylobacter jejuni. Acta Cryst. D 70:442.
• Goyal et al. (2013) Crystallization and preliminary X-ray crystallographic analysis of the curli transporter CsgG. Acta Cryst. F69:1349.

• Fujita et al. (2017) Structural Flexibility of an Inhibitor Overcomes Drug Resistance Mutations in Staphylococcus aureus FtsZ. ACS Chem. Biol. 12:1947.
• Weidenweber et al. (2017) Structure of the acetophenone carboxylase core complex: prototype of a new class of ATP-dependent carboxylases/hydrolases. Sci. Rep. 7:39674.
• Fujita et al. (2017) Identification of the key interactions in structural transition pathway of FtsZ from Staphylococcus aureus. J. Struct. Biol. 198:65.
• Wagner et al. (2016) The methanogenic CO2 reducing-and-fixing enzyme is bifunctional and contains 46 [4Fe-4S] clusters. Science 354:114.
• Demmer et al. (2015) Insights into Flavin-based Electron Bifurcation via the NADH-dependent Reduced Ferredoxin:NADP Oxidoreductase Structure. JBC 290:21985.
• Rekittke et al. (2015) Structure of the GcpE-HMBPP complex from Thermus thermophilius. Biochem. Biophys. Res. Commun.458:246.
• Uchida et al. (2014) Structure and properties of the C-terminal β-helical domain of VgrG protein from Escherichia coli O157. J. Biochem. 155(3):173.

• McDougall et al. (2019) Proteinaceous Nano container Encapsulate Polycyclic Aromatic Hydrocarbons. Sci. Rep. 9:1058.
• De Wijn et al. (2018) Combining crystallogenesis methods to produce diffraction-quality crystals of a psychrophilic tRNA-maturation enzyme. Acta Cryst F 74:747.
• Kumar et al. (2018) Novel insights into the degradation of β-1,3-glucans by the cellulosome of Clostridium thermocellum revealed by structure and function studies of a family 81 glycoside hydrolase. Int. J. Biol. Macromol. 117:890.
• Leal et al. (2018) Crystal structure of DlyL, a mannose-specific lectin from Dioclea lasiophylla Mart. Ex Benth seeds that display cytotoxic effects against C6 glioma cells. Int. J. Biol. Macromol. 114:64.
• Sousa Cavada et al. (2018) Canavalia bonariensis lectin: Molecular bases of glycoconjugates interaction and antiglioma potential. Int. J. Biol. Macromolec. 106:369.
• Ernst et al. (2018) A comparative structural analysis of the surface properties of asco-laccases. PLOS ONEDOI:10.1371/journal.pone.0206589.
• Kumar et al. (2017) Non-classical transpeptidases yield insight into new antibacterials. Nat. Chem. Biol. 13:54.
• Nascimento et al. (2017) Structural analysis of Dioclea lasiocarpa lectin: A C6 cells apoptosis-inducing protein. Int. J. Biochem. Cell Biol. 92:79.
• Cattani et al. (2015) Structure of a PEGylated protein reveals a highly porous double-helical assembly. Nat. Chem. 7:823.
• Boltsis et al. (2014) Non-contact Current Transfer Induces the Formation and Improves the X?ray Diffraction Quality of Protein Crystals. Crystal Growth & Design 14:4347.

• Kampatsikas et al. (2017) In crystallo activity tests with latent apple tyrosinase and two mutants reveal the importance of the mutated sites for polyphenol oxidase activity. Acta Cryst. F 73:491.
• Kolek et al. (2016) A novel microseeding method for the crystallization of membrane proteins in lipidic cubic phase. Acta Cryst. F 72:307.
• Tan et al. (2014) A conformational landscape for alginate secretion across the outer membrane of Pseudomonas aeruginosa. Acta Cryst. D 70:2054.
• Li et al. (2014) Crystallizing Membrane Proteins in the Lipidic Mesophase. Experience with Human Prostaglandin E2 Synthase 1 and an Evolving Strategy. Crystal Growth & Design 14:2034.
• Jacobs et al. (2012) Expression, purification and crystallization of the outer membrane lipoprotein GumB from Xanthomonas campestris. Acta Cryst. F 68:1255.
• Li et al.(2011) Crystallizing Membrane Proteins in Lipidic Mesophases. A Host Lipid Screen. Crystal Growth & Design 11(2):530.
• Shaw Stewart et al. (2011) Random Microseeding: A Theoretical and Practical Exploration of Seed Stability and Seeding Techniques for Successful Protein Crystallization. Crystal Growth & Design 11(8):3432.
• Caffrey et al. (2009) Crystallizing Membrane Proteins Using Lipidic Mesophases. Nat Protoc. 4:706.
• Cherezov et al. (2006) In Meso Structure of the Cobalamin Transporter, BtuB, at 1.95 ? Resolution. J. Mol. Biol. 364:716.