Cloning the biobricks was more
difficult than expected. Ben tried to do digestion/ligation using the
restriction enzymes using the PSB1C3 backbone from BBa_K1017726, but
transformation into E. coli
strain DH10B yielded low efficiency with minimal number of colonies. He
ran sequencing PCR with primers that bound to both the backbone and the
target part. He found the prefix but not the suffix.
Ben and Cheryl tried different sequencing primers that bound to sites
on the genes instead, and re-ran sequencing PCR to no avail. Next, they
tried religating using higher molar ratios 3:1 vector to insert, and
the sequencing PCR ran into the same issue.
We then got a new purified backbone from the distribution well from
caroline and used that to clone. We also used Andrew's CPEC
protocol to clone both the hybrid and normal part. We weren't able to
clone the positive control because for the protocol you need 15-20 bp
overlaps and the primers we had on hand did not allow for that. Also
there was a very similar part on the parts registry so there was no use
sending a part that essentially had the same Ptet and EYFP.
Using PCR purified products, the CPEC cloning had much higher
efficiency than digestion/ligation. We ran colony PCR on the colonies,
checking for both the prefix and suffix, and the colonies that came
from the CPEC had the right bands. We sent in the sequences for
sequence verification and successfully sent in 2 biobrick parts.
Biobrick Submission: 10/8/14
Nitrogenase
Group - Caroline Focht
The original idea was to break the nif cluster from Cyanothece sp.
51142 into six different parts since the entire cluster is upwards of
35 kb. Primers were designed, and the desired fragments were produced
via PCR. After running a gel to confirm the products, it was observed
that some of the PCR reactions had not produced any of the desired
fragments.
Using a temperature gradient and DMSO, all of the fragments
were eventually obtained. The BioBrick backbone pSC1B3 was isolated
from an existing BioBrick part taken from the distribution plate using
PCR and the codes for the BioBrick prefix and suffix as primers. This
successfully produced the pSC1B3 plasmid, into which the six different
fragments were inserted using Andrew Ng’s CPEC
protocol.
The now
complete plasmids, backbone plus insert, were transformed into the E.
coli strain XL1 Blue and plated on LB plates. The E. coli were
cultured
overnight, and four cultures from each plate were selected for colony
PCR the next morning. The colony PCR indicated some positive results,
and the plasmids were extracted from those strains, digested with the
enzymes XbaI and SpeI, and confirmed with a gel.
Only two of the
BioBricks showed correct bands from the enzyme digest. After all of
this was complete, it was discovered that all of our prospective
BioBricks including the two successful ones, all contained one or more
illegal restriction sites, thus invalidating their submission.