Periodic Polypeptides Based on Poly(L-Alanylglycine): Biological Synthesis and Verification of the Structure of A Series of Polymers Containing Tandem —(Alagly)xGlugly— Repeats

The experiments reported herein constitute part of an investigation of the relationship between primary sequence and higher order structure in repetitive polypeptides. Three series of artificial DNAs encoding poly-peptides represented by the general formula + (GlyAla)_nGlyGlu]_m— were constructed and cloned in Escherichia coli.Protein expression was monitored by in-vivo labeling with ^3H-glycine. Protein products were isolated from the cell lysates by stepwise acidification in yields of 20–50 mg/L of culture, and fusion fragments derived from the cloning vectors were removed by cyanogen bromide cleavage. Amino acid sequence analysis verified the expected sequences through the first 40–50 N-terminal residues