IGEM:Harvard/2006/Perry projects

BioBricks assembly

The final constructs

• R0010-B0032-Lpp29-OmpA66-Streptavidin

• R0010-B0032-Lpp29-OmpA159-Streptavidin

The parts

R0010 is a Lac promoter, B0032 is a ribosome binding site (medium strength, same one used in the GFP expression device), Lpp29-OmpA66 and Lpp29-OmpA159 are two versions of the membrane display scaffold.

There are several different versions of streptavidin that may be used. We have BioBricks of strepavidin clones from the Ting lab: wild-type, wild-type + His6tag, and dead, which I refer to as StrepW, StrepH, and StrepD.

Available sequenced and midiprepped parts

In Lpp-OmpA box...

• Lpp29, OmpA66, OmpA159 in pCR-2.1 Topo vector
• Lpp29, OmpA66, OmpA159 in pSB1A2 vector
• Lpp29-OmpA66 in pSB1A2

In StrepW,H,D box...

• StrepW, StrepH, StrepD in pCR-2.1 Topo vector

Available digested and gel purified parts, ready for ligation

• R0010, S/P (CIPed)
• Lpp29, E/S
• Lpp29, S/P (CIPed)
• OmpA66, X/P
• OmpA159, X/P
• Lpp29-OmpA66, S/P (CIPed)
• StrepW, StrepH, StrepD, X/P

• pSB1A2, E/P ("1")
• pSB1A2, E/S ("2")
• pSB1A2, X/P ("3")

BioBricks PCR

We're working on getting BioBricks of single-chain dimeric streptavidin clones from the Aslan lab: SCD-NM (single-chain dimer, not mutant), C2, and E2 (two mutant clones), which I refer to as S, C, and E. I just received a core streptavidin (streptavidin has a full-length version and a functional truncated core version) from the Dr. Takeshi Sano, called pTSA13, which I refer to as pTSA13 or just 13.

There are also two clones of the Lpp-OmpA scaffold which I received recently from the Georgiou lab, 481 (Lpp1-9-OmpA46-66-Bla) and 488 (Lpp1-9-OmpA46-145-Bla).

Goals for week of 8/6/06

Assembly

• Lpp29-OmpA159
• Lpp29-OmpA66-StrepW, H, or D
• R0010-B0032

BioBrick PCR

• SCD-NM, C2, or E2 clones of single-chain dimeric streptavidin from Aslan lab, with PstI site removed by mutagenesis
• pTSA13 streptavidin clone from Sano lab
• 481 or 488 construct of Lpp-OmpA from Georgiou lab

Agenda

Monday

• Inoculate liquid cultures, 3ml LB + 30ul amp(5mg/ml), of R0010 and B0032. You can use a R0010 streak on a carb plate labeled 7/31/06 in the B2 refrigerator, and a B0032 streak on a carb plate labeled 8/2/06. Make sure you start incubating/shaking them late enough in the day that you'll be around in 16 hours the following day to perform the miniprep or to take out and refrigerate/pellet for later miniprep.

• Prepare 25ul double digests using midipreps of Lpp29 (SpeI/PstI), OmpA159 (XbaI/PstI), and Lpp29-OmpA66 (SpeI/PstI) in pSB1A2 (Lpp-OmpA box). You should aim for around 1ug of DNA in each digest.
  • X ul midiprep for ~1ug DNA, 2.5ul Buffer2, 0.5ul SpeI/XbaI, 0.5ul PstI, 0.25ul BSA(100X), Y ul water for total volume of 25ul
    • Y should equal 21.25 minus X. Don't worry about having exactly 0.25ul BSA; just convince yourself there's a little bit of BSA on the end of your pipet tip, and that it's entering your mixture.
  • Incubate at 37dC overnight (12h or so), 80dC for 20min, 4dC forever. There should be a program called "Digest" on either of the two grey PCR machines; just change the 37dC step to whatever time.

• Prepare three PCRs using "S/C/E mut in pET" minipreps and StrepSCDF/StrepSCDRS(5uM) primers in "S,C,E" box, and PCR Supermix in "Primers/Stuff" box.
  • 45ul PCR Supermix + 2ul StrepSCDF(5uM) + 2ul StrepSCDRS(5uM) + 1ul "S, mut in pET" miniprep
  • " + " + " + 1ul "C, mut in pET" miniprep
  • " + " + " + 1ul "E, mut in pET" miniprep
    • Incubate using "PCR PT" program on either grey PCR machine.

• Get primers Lpp9F and OmpA145R from Alain. Reconstitute in (10 times #nmoles) ul EB for a concentration of 100uM. You should vortex for a good 30-40 seconds. Then dilute 5ul of that with 95ul EB for a dilution of 5uM. Then prepare two PCR reactions with the 481 and 488 minipreps in "Misc." box. Also, the OmpA66R primer should be in the "Primers" box at the bottom of the B5 freezer.
  • 45ul PCR Supermix + 2ul Lpp9F(5uM) + 2ul OmpA66R(5uM) + 1ul 481 miniprep
  • 45ul PCR Supermix + 2ul Lpp9F(5uM) + 2ul OmpA145R(5uM) + 1ul 488 miniprep

Tuesday

• (Person A) Treat the Lpp29 and Lpp29-OmpA66 digests with alkaline phosphatase (CIP). To each of the 25ul digests, add 1ul alkaline phosphatase and 3ul 10X phosphatase buffer. Incubate at 37dC for one hour, 4dC forever.
• (Person A) While you're waiting for CIP, pour a 1% 100ml agarose gel.
  • Dissolve 1g agarose in 100ml TBE with microwave at 30-sec intervals. Once the solution is clear, let sit in cold tap water until you can hold the warm bottle comfortably in your hands, then add 5ul EtBr. Swirl until EtBr has disappeared and then pour into a gel frame that has been set even. Use a 15-tooth comb to push all the bubbles down to the bottom of the gel, and then set comb along top. Let gel harden over 15-20min.
• (Person B) While you're waiting for CIP, perform minipreps of R0010 and B0032 liquid cultures from yesterday. Protocol note: I usually include the extra PB step, and elute in 30ul water, letting stand for 5min instead of 1min.
• (Person A) Run gel electrophoresis of digests and PCRs.
  • Add 3ul loading dye to OmpA159 digest, 4ul loading dye to Lpp29 and Lpp29-OmpA66 digests, 6ul loading dye to PCR reactions "S/C/E, mut in pET" and "481" and "488" from yesterday.
  • Load 10ul 1kb+ ladder, entire OmpA159 digest (28ul), entire Lpp29 and Lpp29-OmpA66 digests (33ul), and split up the PCR reactions into two wells for each reaction (28ul in each well).
  • Run gel for 45min at 130V. Make sure the gel apparatus is clean and has fresh TBE buffer.
• (Person C) Image gel and cut out bands. First, prelabel and preweigh empty 1.5ml Eppendorf tubes on the scale in the back with the sliding windows, and record on the tube itself how many milligrams it weighed. Also, set the heatblock to 50dC.
  • Expected band sizes, approximate:
    • Lpp29, SpeI/PstI: 2200bp
    • OmpA159, XbaI/PstI: 350bp
    • Lpp29-OmpA66, SpeI/PstI: 150bp
    • S/C/E PCRs: 850bp and 350bp. Cut out the 850 bp and NOT the 350bp band.
    • 481 PCR: 90bp
    • 488 PCR: 330bp
  • Cut out bands, collect gel slices in tubes, weigh the tubes again and subtract to determine milligrams of gel slice. Use this weight in milligrams as your gel volume for gel extraction. Protocol note: I include the extra QG step, and elute in 30ul water, letting stand for 5min instead of 1min. There is a small bottle of isopropanol over my bench, B4.

• Ligation/Topo cloning. This is a rather large undertaking (four ligations, six Topo clonings), so it might be helpful to split it up between two sixeople.
  • Samples needed
    • Lpp29, SpeI/PstI
    • OmpA159, XbaI/PstI
    • Lpp29-OmpA66, SpeI/PstI
    • StrepW, StrepH, and StrepD, XbaI/PstI (in the "gel-purified digests" box)
    • S/C/E PCRs from yesterday, gel-purified today
    • 481 and 488 PCRs from yesterday, gel-purified today
    • pTSA13 PCR, gel-purified 8/4/06 (in pTSA13 box, labeled "lanes 2+3")
  • Ligations
    • 2.5ul Lpp29 S/P + 7.5ul OmpA159 X/P
    • 2.5ul Lpp29-OmpA66 S/P + 7.5ul StrepW, X/P
    • 2.5ul Lpp29-OmpA66 S/P + 7.5ul StrepH, X/P
    • 2.5ul Lpp29-OmpA66 S/P + 7.5ul StrepD, X/P
      • Mix these, add 10ul "Vial 1" ligase buffer (found in "primers/stuff" box, or as part of Rapid DNA ligase kit), and mix again. Then add 1ul "Vial 3" DNA ligase, and mix thoroughly. Let sit at room temperature 10min.
  • Topo clonings. Use TOPO-TA cloning kit. I would suggest opening a new kit, which should be in the -80 freezer. I was having trouble with my last Topo cloning.
    • 4ul gel-purified PCR "S"
    • 4ul gel-purified PCR "C"
    • 4ul gel-purified PCR "E"
    • 4ul gel-purified PCR "481"
    • 4ul gel-purified PCR "488"
    • 4ul gel-purified PCR "pTSA13"
      • Mix each of these with 1ul salt solution and 1ul Topo vector. Let sit at room temperature 10min.

• Transformations. You can refrigerate the ligation/Topo cloning reactions for later if you don't have time to do the transformation today. Again, it's a large undertaking, so it might be better with two people.
  • You'll be doing ten transformations: the four ligations and six Topo clonings from above. I would thaw on ice three tubes of Top10 cells, and then aliquot 18ul into ten 1.5ml Eppendorf tubes. After you've aliquotted the cells into different tubes, pipet in the respective 21ul ligation reaction or 6ul Topo cloning, tap the tubes 5-10 times to mix, and leave the cells on ice for 30min or longer. While you're waiting, make sure the heatblock is at 42dC, and squirt some water in the holes to better heat contact during the heat shock step, which is next. Heat-shock the cells at 42dC on heatblock for 30 sec, and cool on ice for 2min. Add 200ul SOC media to each tube, and leave in the 37dC shaker for 1 hour or more. While they're shaking, leave four carb plates (for ligations) and three kan plates (for Topo clonings) to warm in the plates incubator. If there are no kan plates, you can use carb or amp plates as well for Topo clonings because the Topo vector is both amp and kan resistant. Then under a flame, pipet the whole culture onto the plate and spread with a plastic spreader, and leave the plates agar side up in the plates incubator for 15-16 hours.