title: Chemoenzymatic synthesis of poly(L-alanine) in aqueous environment.
abstract: L-alanine ethyl ester was polymerized into poly(L-alanine) (polyAla), one of the insoluble polypeptides, by papain in aqueous buffer at varying pH. At neutral pH, a maximum chain length of 11 repeats was observed. These polymers were dominated by random coiled structure and demonstrated a lack of patterned macromolecular assembly. Under alkaline conditions, longer polymer chain lengths were achieved, and the maximum chain length was 16 repeats. These longer chains showed distinct β-sheet formation and were capable of fibril assembly. The present study reports on chemoenzymatic synthesis of a hydrophobic homopolypeptide under aqueous conditions as well as demonstrates a chain length dependency of secondary structure formation and macromolecular assembly of chemoenzymatically synthesized polyAla, providing a new insight into material design of polypeptide.
authors.affiliation: Enzyme Research Team, RIKEN Biomass Engineering Program, RIKEN, Wako-shi, Saitama, Japan.
authors.forename: Peter James
authors.initials: PJ
authors.lastname: Baker
authors.forename: Keiji
authors.initials: K
authors.lastname: Numata
mesh_terms: D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D015394:Molecular Structure; D010206:Papain / Q000737:chemistry / Q000378:metabolism*; D010455:Peptides / Q000138:chemical synthesis* / Q000378:metabolism*; D014867:Water / Q000737:chemistry / Q000378:metabolism*
chemical_list: D010455:Peptides; D014867:Water; C019529:polyalanine; D010206:Papain