Chemical and biosynthetic approaches to the production of novel polypeptide materials.
Three approaches to the synthesis of the repetitive copolypeptide [(GlyAla)3-GlyProGlu]n (1) are described. Direct chemical synthesis of 1 via classical solution methods required 18 steps and afforded a polydisperse product with an average molecular weight of less than 10,000. Two alternative genetic strategies were also explored. In the first, chemically synthesized DNA oligomers were self-ligated to produce a population of multimers, which were fitted with translational start and stop signals and inserted into an expression plasmid containing the lambda PL promoter and a synthetic ribosome binding site. Transformation of E. coli led to the isolation of a stable recombinant plasmid carrying an insert encoding 12 repeats of sequence 1. Attempts to identify polypeptide 1 after induction of transformed cultures were unsuccessful. A second strategy, generating a tripartite derivative of sequence 1 carrying short N- and C-terminal extensions, afforded excellent yields of product. The relative merits of chemical and genetic approaches to repetitive polypeptide materials are discussed.
McGrath
K P
KP
Department of Polymer Science, University of Massachusetts, Amherst 01003.
Tirrell
D A
DA
Kawai
M
M
Mason
T L
TL
Fournier
M J
MJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods*; D004247:DNA / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D008969:Molecular Sequence Data; D010452:Peptide Biosynthesis; D010455:Peptides / Q000138:chemical synthesis* / Q000235:genetics; D010957:Plasmids
D010455:Peptides; D004247:DNA