title: n→π* interactions in poly(lactic acid) suggest a role in protein folding.
abstract: Poly(lactic acid) (PLA) is a versatile synthetic polyester. We noted that this depsipeptide analog of polyalanine has a helical structure that resembles a polyproline II helix. Using natural bond orbital analysis, we find that n→π* interactions between sequential ester carbonyl groups contribute 0.44 kcal mol(-1) per monomer to the conformational stability of PLA helices. We conclude that analogous n→π* interactions could direct the folding of a polypeptide chain into a polyproline II helix prior to the formation of hydrogen bonds between backbone amides.
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706-1322, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Newberry
authors.forename: Ronald T
authors.initials: RT
authors.lastname: Raines
mesh_terms: D006860:Hydrogen Bonding; D019344:Lactic Acid / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D011789:Quantum Theory
chemical_list: D010455:Peptides; D011091:Polyesters; D011108:Polymers; D011506:Proteins; C011083:polyproline; D019344:Lactic Acid; C033616:poly(lactide)
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