The thermal stability of bovine beta-lactoglobulin (BLG) has been enhanced by the introduction of an additional disulfide bond. Wild-type BLG has two disulfide bonds, C106-C119 and C66-C160, with a free cysteine at position 121. We have designed, with the aid of molecular modeling calculations, two mutants of a recombinant BLG (rBLG), L104C and A132C. Molecular dynamics simulations were performed at 300K to study the effect of these alterations on the conformation of the protein. These mutants were then created by site-directed mutagenesis and purified from Escherichia coli carrying a tac expression vector using a two-step renaturation method. Formation of disulfide linkages in the correct arrangement, as designed, was confirmed by peptide mapping. In contrast to wild-type rBLG, which polymerizes at temperatures > 65 degrees C, neither of the mutant proteins polymerized. The conformational stability of the L104C and A132C mutant proteins against thermal denaturation has been substantially increased (8-10 degrees C) as compared with wild-type rBLG. Furthermore, the A132C rBLG exhibits an enhanced stability against denaturation by guanidine hydrochloride as compared with the wild-type or L104C rBLG.

Movement analysis is a useful procedure for designers of protective apparel, both as a source of information needed to design more mobile apparel and as a means of judging the performance of various apparel models. This study focused on the development of a movement analysis test for the investigation of movement problems associated with disposable coveralls used as protection for asbestos abatement workers. The test was based on a technique developed by Crow and Dewar in which a honeycomb pattern of slashes made over the surface of a garment could be observed to open in response to the pressure exerted by the body as the wearer moved. (Crow and Dewar, 1986) [1] This allowed the location, direction, and degree of stress to be seen and recorded on videotape. A new coverall design was developed based on information from the movement analysis test. The test was also used to evaluate the performance of the new design compared to the original design. The results of the movement analysis test and the results of a field test of the two coverall styles both supported the conclusion that the redesigned coveralls provided workers with greater mobility than the original style of coverall.

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