Characterization by spectroscopic, kinetic and equilibrium methods of the interaction between recombinant human cystatin A (stefin A) and cysteine proteinases.

The near-UV spectroscopic changes induced by the binding of recombinant human cystatin A to papain were appreciably different from those induced by cystatin C, reflecting mainly interactions involving the single tryptophan of cystatin C, Trp-106. Cystatin A bound tightly and rapidly to papain and cathepsin L, with dissociation equilibrium constants of approximately 10(-11)-10(-13) M and association rate constants of 3 x 10(6)-5 x 10(6) M-1.s-1.

Protein kinase C phosphorylates two of the four known syndecan cytoplasmic domains in vitro.

The transmembrane heparan sulfate proteoglycans of the syndecan family are implicated to participate in several cellular reactions which are dependent on protein kinase C. We have used an in vitro assay to assess whether any of the Peptides corresponding to the complete cytoplasmic domains of rat syndecans 1 through 4 were used as substrates for the enzyme. The syndecan-2 (fibroglycan) and syndecan-3 (N-syndecan) peptides were both found to be phosphorylated by protein kinase C with Kms of 15 +/- 3 microM and 85 +/- 25 microM, respectively, while the syndecan-1 and -4 peptides were not phosphorylated under the conditions used.

Interaction of cysteine proteinases with recombinant kininogen domain 2, expressed in Escherichia coli.

The calpain-binding domain 2 of the kininogens, the major plasma inhibitors of cysteine proteinases, was expressed in Escherichia coli. Expression of soluble protein was optimal at 15 degrees C and was augmented by growing the bacteria in sorbitol and betaine. The recombinant domain showed high affinity (Ki 0.

Design, expression, and crystallization of recombinant lectin from the garden pea (Pisum sativum).

The propeptide form of the lectin from the garden pea (Pisum sativum agglutinin) has been expressed in Escherichia coli by attaching its cDNA to an inducible promoter. By a number of criteria, including the ability to form dimers, hemagglutination titer, Western blot, and enzyme-linked immunosorbent assay, the resulting propeptide molecule is virtually indistinguishable from the mature proteolytically processed lectin isolated from peas. Preliminary crystallization experiments using the recombinant propeptide lectin yield crystals in space group P2(1)2(1)2(1) with a = 64.

Sulfate transport-deficient mutants of Chinese hamster ovary cells. Sulfation of glycosaminoglycans dependent on cysteine.

We isolated 59 Chinese hamster ovary cell mutants defective in 35SO4 incorporation into glycosaminoglycans. Thirty-five mutants incorporated [6-3H]glucosamine into glycosaminoglycans normally, suggesting that they were specifically impaired in sulfate incorporation. Cell hybridization studies revealed that the 35 mutants defined a unique complementation group.