A new family of insecticidal crystal proteins was discovered by screening sporulated Bacillus thuringiensis cultures for oral activity against western corn rootworm (WCR) larvae. B. thuringiensis isolates PS80JJ1, PS149B1, and PS167H2 have WCR insecticidal activity attributable to parasporal inclusion bodies containing proteins with molecular masses of ca.… (More)
Field tests of corn co-expressing two new delta-endotoxins from Bacillus thuringiensis (Bt) have demonstrated protection from root damage by western corn rootworm (Diabrotica virgifera virgifera LeConte). The level of protection exceeds that provided by chemical insecticides. In the bacterium, these proteins form crystals during the sporulation phase of the… (More)
The GroEL/GroES chaperonin system acts as a passive anti-aggregation cage for refolding rubisco and rhodanese, and not as an active unfolding device. Refolding aconitase is too large to enter the cage but reversible binding to GroEL reduces its aggregration. Unexpectedly, confinement in the cage increases the rate of refolding of rubisco, but not rhodanese.
Some proteins avoid aggregation and fold more rapidly by being confined within a cage provided by the chaperonins GroEL and GroES. Chaperoning by confinement is much more efficient than chaperoning outside the cage. To survive in a competitive world, cells must optimise both the rate of production and the yield of correctly folded proteins. Partially folded… (More)
The involvement of two types of molecular chaperone in folding newly synthesized proteins can be rationalized in terms of the crowded nature of the intracellular environment. Recent work sheds light on how these chaperones recognise their substrates and protect them from the problems of macromolecular crowding.