Structural and functional influence of enzyme-antibody interactions: effects of eight different monoclonal antibodies on the enzymatic activity of Escherichia coli tryptophan synthase

Biochemistry ◽  
1984 ◽  
Vol 23 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Lisa Djavadi-Ohaniance ◽  
Bertrand Friguet ◽  
Michel E. Goldberg
Keyword(s):  
Escherichia Coli ◽  
Monoclonal Antibodies ◽  
Enzymatic Activity ◽  
Tryptophan Synthase ◽  
Antibody Interactions

Nascent chains: folding and chaperone interaction during elongation on ribosomes

1995 ◽  
Vol 348 (1323) ◽  
pp. 89-95 ◽  
Keyword(s):  
Escherichia Coli ◽  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Spike Protein ◽  
Tryptophan Synthase ◽  
Bacteriophage P22 ◽  
Folding Intermediates ◽  
Tail Spike ◽  
Polypeptide Chains

Monoclonal antibodies that detect folding intermediates in vitro were used to monitor the appearance of folded polypeptide chains during their synthesis on the ribosomes. Nascent immunoreactive chains of the bacteriophage P22 tail-spike protein and of the Escherichia coli β 2 subunit of tryptophan-synthase were thus identified, suggesting that they can fold on the ribosomes. Moreover, the immunoreactivity of ribosome- bound tryptophan-synthase β-chains of intermediate lengths was shown to appear with no detectable delay compared to their synthesis. This suggested that β-chains start folding during their elongation on the ribosomes. However, newly synthesized incomplete β-chains were shown to interact with chaperones while still bound to the ribosome. Because of the peculiar properties of the epitope recognized by the anti- tryptophan-synthase monoclonal antibody used, it could not be concluded whether the immunoreactivity of the nascent β-chains resulted from their ability to fold cotranslationally or from their association with chaperones which might maintain them in an unfolded, immunoreactive state.

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