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protocol:spcsh3

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Materials

FPLC Buffers

  • Buffer A (1L) & B (1L)
    • 2L ddH2O
    • Tris (MW121.4) 4.84g and adjust pH to 8.0
    • Divide it into 2 parts; one part as Buffer A
    • The other Part + NaCl (MW:58.44) 58.44g + EDTA (372.24) 0.372g → Buffer B
  • Buffer C (1L)
    • 1L H2O
    • Citric Acid (MW210.14) 3.115g
    • Citric Na (MW294.10) 1.523g
    • EDTA (MW 372.24) 0.372g
    • NaCl (MW58.44) 8.76g

Protein Expression

  • Put 5 uL stock E. coli. to 5 mL of LB media, and shake it overnight at 37C, 225rpm.
  • Transfer the culture above into 1L expression medium with Amp; grow @37C,225rpm unitl OD600=0.5~0.6.
  • Induce by 1mM 1PTG-D2O and further shaked for 4 hours
  • Centrifuge the culture @8000rpm,4C for 15min; store in deep freezer or go head for French Press

French Press

  • Resuspend cells in 20mL buffer A and keeps it always in ice box; Add 50uL 2M MgCl2 (final_C=5mM); Add 250U Benzonase (Novagen); 2 small tablets Complete (Proteinase Inhibitor, Roche)
  • The suspension is twice French pressed. Instruction
  • Centrifuge @18000rpm,4C for 30min; get the supernanant (Keep it always in ice box)

Protein Purification

  • QFF Ion-Exchange column (2 column connected together, column size:2X5mL=10mL)
    • Connect the tubling of FPLC; install the 5mL sample loop; wash the column using ddH2O if it is stored in 20% Alcohol.
    • Run Program #22 to wash and equilibrate the column
    • Filter the supernanant by syringe filter
    • Run Program #21 to apply the sample (you may need repeat several times)
    • Run Program #23 to run the column; colect the proper fractions

  • Gel-filtration column
    • The positive fractions are pooled and pH are adjusted to 3.5 by 1M citric acid (15ml+220ul)
    • Replace the 20% Alcohol in the column with Buffer C if necessary
    • Concentrate it to ~4mL by centriprep (Millipore Corp)
    • Apply the sample to sample loop and run Program #24 to run the column

Prepare NMR sample

  • Run SDS-PAGE to check the fractions
  • Prepare buffer for NMR sample
    • 0.02% NaN2
  • Pool the proper fractions; concentrate it using CentriPrep several times to exchange the buffer to NMR buffer
  • Concentrate the sample to ~200uL, add 10% D2O
protocol/spcsh3.txt · Last modified: 2017/07/11 09:52 by 127.0.0.1