Difference between revisions of "Part:BBa K523014"

Revision as of 13:24, 13 September 2011

Plac + LacZ + bglX

The E. coli periplasmic β-glucosidase gene bglX under the control of the lac promoter. The native ribosome binding site is present.

Usage and Biology

The BglX β-glucosidase is expected to be localised to the periplasm. It ought to be capable of breaking down cellobiose.

Experiment

We conducted two assays, comparing the activity of this part (bglX) with that of the exoglucanase cex (BBa_K118022) under the control of the lac promoter (yielding BBa_K523016) on two different substrates:

• 4-methylumbelliferyl-beta-D-glucuronide (MUG, left photo). This substrate mimics cellobiose.
• Something else (MUC, right photo). This substrate mimics cellulose.

Both substrates produce a fluorescent product when cleaved. Our plates below shows the results of placing cell lysate and cell debris on an MUG plate. Present on both plates are:

• Left side of plate: JM109 expressing this part, K523014
• Right side of plate: JM109 expressing exoglucanase cex, BBa_K523016
• Bottom of plate: JM109 cells

MUG assay. bglX on left, cex on right.		MUC assay. bglX on left, cex on right.

As can be seen, bglX is capable of degrading MUG (the cellobiose mimic) while exoglucanase displays much weaker activity. By contrast, exoglucanase is much better at degrading MUC.

Sequence and Features