title: Reevaluation of the D-amino acid compatibility with the elongation event in translation.
abstract: The compatibility of D-amino acids with peptide elongation during translation has been examined in several studies. However, some of the studies have reported that D-amino acids are incompatible with translation, whereas others have reported that D-amino acids are incorporated into polypeptides. Here, we have reevaluated the incorporation of a series of D-amino acids into the nascent chain of short peptides with a reprogrammed genetic code by using the flexible in vitro translation (FIT) system. The FIT system enables the compatibility of each D-amino acid with elongation to be assessed quantitatively in the absence of potential competitors. The incorporation efficiencies were determined by Tricine-SDS-PAGE and the full-length peptide was detected by MALDI-TOF-MS. The D-amino acids were categorized into three groups based on their incorporation efficiencies relative to the corresponding L-amino acid. The D-isomers in group I showed efficiencies of 40% or higher (Ala, Ser, Cys, Met, Thr, His, Phe, and Tyr), and those in group II showed efficiencies of 10-40% (Asn, Gln, Val, and Leu). The D-amino acids in group III produced truncated peptides or no detectable full-length peptides (Arg, Lys, Asp, Glu, Ile, Trp, and Pro). When group I D-amino acids were used consecutively or were alternated with L-amino acids, this completely inhibited their elongation. However, when two or three L-amino acids were inserted between the D-amino acids, the double-incorporation efficiency was restored. Our results quantitatively reveal the compatibility of D-amino acids with peptide elongation and raise new questions about the mechanism of D-amino acid selection and incorporation by the ribosome.
authors.affiliation: Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
authors.forename: Tomoshige
authors.initials: T
authors.lastname: Fujino
authors.forename: Yuki
authors.initials: Y
authors.lastname: Goto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Suga
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Murakami
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000596:Amino Acids; D010455:Peptides